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Sample records for test preparation blacks

  1. Cold Preparation of Heroin in a Black Tar Market.

    Science.gov (United States)

    Roth, Alexis M; Armenta, Richard F; Wagner, Karla D; Strathdee, Steffanie A; Goldshear, Jesse L; Cuevas-Mota, Jazmine; Garfein, Richard S

    2017-07-29

    Black tar heroin is typically prepared for injection with heat which decreases the risk of HIV transmission by inactivating the virus. We received reports that persons who inject drugs (PWID) in Tijuana, Baja California, Mexico, a black tar heroin market, were using only water to dissolve heroin. Because Tijuana abuts San Diego County, CA, United States, we undertook the present analyses to determine the prevalence of this practice among PWID in San Diego, California. PWID completed quarterly behavioral assessments and serological testing for blood-borne viruses. Bivariate and multivariable logistic regression models were constructed to assess for individual, social, and structural correlates of preparing heroin without heat within the preceding 6 months. Nearly half of black tar heroin users (149/305) reported they had prepared heroin without heat within 6 months. In multivariable analysis, cold preparation was independently associated with younger age (10 year decrease; AOR = 1.25; 95% CI 1.03, 1.53), more drug injecting acquaintances (per 5 acquaintance increase; AOR = 1.05; 95% CI 1.01, 1.09) and prefilled syringe use (injecting drugs from syringes that are already filled with drugs before purchase; AOR = 1.86; 95% CI 1.14, 3.02). Conclusions/Importance: To our knowledge, this is the first paper to report that PWID living in a black tar heroin market are preparing heroin without heat. Additional research is needed to determine whether this is an endemic practice or PWID are engaging in new forms of drug preparation in response to changes in the environment.

  2. Preparation of carbon black masterbatch for PET using polymeric dispersing agents

    Energy Technology Data Exchange (ETDEWEB)

    Oh, D.H. [Kyungpook National University, Taegu (Korea, Republic of); Lim, J.C. [Pukyong National University, Pusan (Korea, Republic of); Seo, K.H. [Yeungnam College of Science and Technology, Taegu (Korea, Republic of)

    1999-03-01

    Three kinds of copolyesters, dispersing agents, were synthesized from the polycondensation reaction of dimethylterephthalate (DMT), dimethylisophthalate (DMI), sebacic acid (SA), and 1,4-butanediol (BD). Carbon black masterbatches were prepared by mixing carbon black into the dispersing agents (1 : 1.3 weight ratio) in a Brabender Plasticorder Using single screw extruder, masterbatches were compounded with poly(ethylene terephthalate) in 3 wt% concentration and mechanical properties of the compounds were investigated Gel permeation chromatography data implied that thermal degradation of polymeric dispersing agents was not significant through dispersion. Capillary rheometer test showed that PBTI has the highest viscosity and shear sensitivity among the there dispersing agents. Volume resistivities of masterbatch and transmission electron micrographs showed that dispersity of carbon black was improved with increasing melt viscosity of dispersing agent. The ultimate performance and mechanical characteristics of carbon black filled PET compounds depended directly on dispersion quality of the carbon black in masterbatch. Mechanical properties of compounds were improved with increasing dispersity of carbon black and with increasing content of rigid aromatic group in the copolyester dispersing agent. 30 refs., 9 figs., 5 tabs.

  3. Destroying black holes with test bodies

    Energy Technology Data Exchange (ETDEWEB)

    Jacobson, Ted [Center for Fundamental Physics, University of Maryland, College Park, MD 20742-4111 (United States); Sotiriou, Thomas P, E-mail: jacobson@umd.ed, E-mail: T.Sotiriou@damtp.cam.ac.u [Department of Applied Mathematics and Theoretical Physics, Centre for Mathematical Sciences, University of Cambridge, Wilberforce Road, Cambridge, CB3 0WA (United Kingdom)

    2010-04-01

    If a black hole can accrete a body whose spin or charge would send the black hole parameters over the extremal limit, then a naked singularity would presumably form, in violation of the cosmic censorship conjecture. We review some previous results on testing cosmic censorship in this way using the test body approximation, focusing mostly on the case of neutral black holes. Under certain conditions a black hole can indeed be over-spun or over-charged in this approximation, hence radiative and self-force effects must be taken into account to further test cosmic censorship.

  4. Destroying black holes with test bodies

    International Nuclear Information System (INIS)

    Jacobson, Ted; Sotiriou, Thomas P

    2010-01-01

    If a black hole can accrete a body whose spin or charge would send the black hole parameters over the extremal limit, then a naked singularity would presumably form, in violation of the cosmic censorship conjecture. We review some previous results on testing cosmic censorship in this way using the test body approximation, focusing mostly on the case of neutral black holes. Under certain conditions a black hole can indeed be over-spun or over-charged in this approximation, hence radiative and self-force effects must be taken into account to further test cosmic censorship.

  5. Tensile properties of carbon black-filled natural rubber latex films using two different approaches of film preparation

    Science.gov (United States)

    Jarkasi, Siti Aisyah; Samsuri, Azemi; Hashim, M. Y. Amir; Kamarun, Dzaraini

    2017-09-01

    A study was structured to investigate the effects of two different approaches of black-filled NRL films preparation on tensile strengths and tensile stress at 100% strain (M100). In the "First Approach", carbon black dispersion was added into the NRL and mixed using mechanical stirrer. Then the black-filled NRL was coagulated with acetic acid and dried to form NR black-filled masterbatch. This black-filled NR masterbatch was then masticated and mixed with other compounding ingredients on the 2-roll mill. In the "Second Approach", carbon black dispersion was mixed with NRL plus all other compounding ingredients using a mechanical stirrer at high mechanical stirring speed (200 rpm) for 3 hrs. Tensile test-pieces from these two rubber specimens were tested according to ISO37. It was observed that the tensile strengths are affected by both methods. In the case of masticated latex masterbatch, the black-filled NRL films gave higher tensile strength (25-27 MPa) as compared to un-masticated black-filled NRL films (11-17 MPa). The optimum amount of filler loading for highest tensile strength in both approaches was 20 phr of carbon black. However these different approaches did not give significant effect to the elongation at break, EB and M100. SEM images of samples prepared from both approaches suggested that the dispersion of filler in the rubber matrix was better in the masticated samples compared to the un-masticated samples. The reason for the difference in the tensile strength between the two black-filled rubbers might be associated with the degree of dispersions and the uniformity of the dispersions within the rubber matrix. The first mixing approach involved high mechanical shearing action during mastication and mixing process on the 2-roll mill. The high shearing actions were able to breakdown filler aggregates efficiently and distributed the dispersed filler uniformly within the rubber matrix. In the second approach, the breakdown of filler aggregates relied on

  6. Food consumption and growth rates of juvenile black carp fed natural and prepared feeds

    Science.gov (United States)

    Hodgins, Nathaniel C.; Schramm, Harold L.; Gerard, Patrick D.

    2014-01-01

    The introduced mollusciphagic black carp Mylopharyngodon piceus poses a significant threat to native mollusks in temperate waters throughout the northern hemisphere, but consumption rates necessary to estimate the magnitude of impact on mollusks have not been established. We measured food consumption and growth rates for small (77–245 g) and large (466–1,071 g) triploid black carp held individually under laboratory conditions at 20, 25, and 30°C. Daily consumption rates (g food · g wet weight fish−1·d−1·100) of black carp that received prepared feed increased with temperature (small black carp 1.39–1.71; large black carp 1.28–2.10), but temperature-related increases in specific growth rate (100[ln(final weight) - ln(initial weight)]/number of days) only occurred for the large black carp (small black carp −0.02 to 0.19; large black carp 0.16–0.65). Neither daily consumption rates (5.90–6.28) nor specific growth rates (0.05–0.24) differed among temperatures for small black carp fed live snails. The results of these laboratory feeding trials indicate food consumption rates can vary from 289.9 to 349.5 J·g−1·d−1 for 150 g black carp receiving prepared feed, from 268.8 to 441.0 J·g−1·d−1for 800 g black carp receiving prepared feed, and from 84.8 to 90.2 J·g−1·d−1 for 150 g black carp that feed on snails. Applying estimated daily consumption rates to estimated biomass of native mollusks indicates that a relatively low biomass of bla

  7. The Effect of Black Peers on Black Test Scores

    Science.gov (United States)

    Armor, David J.; Duck, Stephanie

    2007-01-01

    Recent studies have used increasingly complex methodologies to estimate the effect of peer characteristics--race, poverty, and ability--on student achievement. A paper by Hanushek, Kain, and Rivkin using Texas state testing data has received particularly wide attention because it found a large negative effect of school percent black on black math…

  8. Dynamics of test black holes

    International Nuclear Information System (INIS)

    Epikhin, E.N.

    1981-01-01

    A concept of a test object is introduced. This definition includes also small black holes. Reduced approximation of testing permits to unambiguously introduce a concept of background space-time. Dynamic values for test objects are introduced by means of the Noether theorem which gave the possibility to covariantly generalize pseudotensor of the Papapetru energy-momentum for the case of curved background space-time. Additional use of radiation approximation and the accountancy of the zero and first momenta of dynamic values lead to the conclusion that motion of the test object (including small black holes) is subordinated to the Matthiessen-Papapetru equations. The above results are testified to the accountancy of a proper gravitational field of the test object in integrated dynamic values [ru

  9. Black hole based tests of general relativity

    International Nuclear Information System (INIS)

    Yagi, Kent; Stein, Leo C

    2016-01-01

    General relativity has passed all solar system experiments and neutron star based tests, such as binary pulsar observations, with flying colors. A more exotic arena for testing general relativity is in systems that contain one or more black holes. Black holes are the most compact objects in the Universe, providing probes of the strongest-possible gravitational fields. We are motivated to study strong-field gravity since many theories give large deviations from general relativity only at large field strengths, while recovering the weak-field behavior. In this article, we review how one can probe general relativity and various alternative theories of gravity by using electromagnetic waves from a black hole with an accretion disk, and gravitational waves from black hole binaries. We first review model-independent ways of testing gravity with electromagnetic/gravitational waves from a black hole system. We then focus on selected examples of theories that extend general relativity in rather simple ways. Some important characteristics of general relativity include (but are not limited to) (i) only tensor gravitational degrees of freedom, (ii) the graviton is massless, (iii) no quadratic or higher curvatures in the action, and (iv) the theory is four-dimensional. Altering a characteristic leads to a different extension of general relativity: (i) scalar–tensor theories, (ii) massive gravity theories, (iii) quadratic gravity, and (iv) theories with large extra dimensions. Within each theory, we describe black hole solutions, their properties, and current and projected constraints on each theory using black hole based tests of gravity. We close this review by listing some of the open problems in model-independent tests and within each specific theory. (paper)

  10. Test fields cannot destroy extremal black holes

    International Nuclear Information System (INIS)

    Natário, José; Queimada, Leonel; Vicente, Rodrigo

    2016-01-01

    We prove that (possibly charged) test fields satisfying the null energy condition at the event horizon cannot overspin/overcharge extremal Kerr–Newman or Kerr–Newman–anti de Sitter black holes, that is, the weak cosmic censorship conjecture cannot be violated in the test field approximation. The argument relies on black hole thermodynamics (without assuming cosmic censorship), and does not depend on the precise nature of the fields. We also discuss generalizations of this result to other extremal black holes. (paper)

  11. Detection and identification of "new" beta-agonists in black-market preparations

    NARCIS (Netherlands)

    van Ginkel LA; Stephany RW; van Rossum HJ; Visser T; den Engelsman T; de Jong APJM; Jacquemijns M; Zomer G

    1992-01-01

    In several "black-market" used for growth promotion preparations new compounds were found belonging to the group of N-phenylethanolamines with structures very similar to compounds known to be used for veal calf and cattle production, the so called beta-agonists. The two most important

  12. Transfer of ochratoxin A from raw black tea to tea infusions prepared according to the Turkish tradition.

    Science.gov (United States)

    Toman, Jakub; Malir, Frantisek; Ostry, Vladimir; Kilic, Mehmet Akif; Roubal, Tomas; Grosse, Yann; Pfohl-Leszkowicz, Annie

    2018-01-01

    Ochratoxin A (OTA) is a natural contaminant of food including tea with multiple toxic effects, which poses a threat to human health. In terms of lifestyle, the Turkish population is a frequent visitor of tearooms, and the traditional Turkish tea preparation is one of the most popular ways of preparing tea infusion. The aim of this study was to investigate OTA transfer from raw black tea to the tea infusion prepared according to the Turkish tradition. A high-performance liquid chromatography method with a limit of quantification of 0.35 ng g -1 was used for OTA determination. The OTA amount in raw black teas from Turkey ranged from ≤0.35 ng g -1 up to 56.7 ng g -1 . An homogenised sample of black tea naturally contaminated with 55.0 ng g -1 was used to prepare infusions. The OTA transfer from the black tea to the infusion was found to be 41.5% ± 7%. These data are important for the realisation of a 'Total Diet study' (TDS). The TDS can be a complementary tool to estimate the population dietary exposure to OTA across the entire diet by analysing main foods prepared 'as consumed' (tea infusions) and not 'as purchased' (raw tea). © 2017 Society of Chemical Industry. © 2017 Society of Chemical Industry.

  13. Black-hole spectroscopy: testing general relativity through gravitational-wave observations

    Energy Technology Data Exchange (ETDEWEB)

    Dreyer, Olaf [Perimeter Institute of Theoretical Physics, 35 King Street North, Waterloo, Ontario, N2J 2G9 (Canada); Kelly, Bernard [Center for Gravitational Wave Physics, Center for Gravitational Physics and Geometry and Department of Physics, 104 Davey Laboratory, University Park, PA 16802 (United States); Krishnan, Badri [Max Planck Institut fuer Gravitationsphysik, Am Muehlenberg 1, D-14476 Golm (Germany); Finn, Lee Samuel [Center for Gravitational Wave Physics, Center for Gravitational Physics and Geometry, Department of Physics and Department of Astronomy and Astrophysics, 104 Davey Laboratory, University Park, PA 16802 (United States); Garrison, David [University of Houston, Clear Lake, 2700 Bay Area Bvd, Room 3531-2, Houston, TX 77058 (United States); Lopez-Aleman, Ramon [Physical Sciences Department, University of Puerto Rico, Rio Piedras Campus, Rio Piedras, Puerto Rico 00931 (Puerto Rico)

    2004-02-21

    Assuming that general relativity is the correct theory of gravity in the strong-field limit, can gravitational-wave observations distinguish between black holes and other compact object sources? Alternatively, can gravitational-wave observations provide a test of one of the fundamental predictions of general relativity: the no-hair theorem? Here we describe a definitive test of the hypothesis that observations of damped, sinusoidal gravitational waves originate from a black hole or, alternatively, that nature respects the general relativistic no-hair theorem. For astrophysical black holes, which have a negligible charge-to-mass ratio, the black-hole quasi-normal mode spectrum is characterized entirely by the black-hole mass and angular momentum and is unique to black holes. In a different theory of gravity, or if the observed radiation arises from a different source (e.g., a neutron star, strange matter or boson star), the spectrum will be inconsistent with that predicted for general relativistic black holes. We give a statistical characterization of the consistency between the noisy observation and the theoretical predictions of general relativity and a demonstration, through simulation, of the effectiveness of the test for strong sources.

  14. Black-hole spectroscopy: testing general relativity through gravitational-wave observations

    International Nuclear Information System (INIS)

    Dreyer, Olaf; Kelly, Bernard; Krishnan, Badri; Finn, Lee Samuel; Garrison, David; Lopez-Aleman, Ramon

    2004-01-01

    Assuming that general relativity is the correct theory of gravity in the strong-field limit, can gravitational-wave observations distinguish between black holes and other compact object sources? Alternatively, can gravitational-wave observations provide a test of one of the fundamental predictions of general relativity: the no-hair theorem? Here we describe a definitive test of the hypothesis that observations of damped, sinusoidal gravitational waves originate from a black hole or, alternatively, that nature respects the general relativistic no-hair theorem. For astrophysical black holes, which have a negligible charge-to-mass ratio, the black-hole quasi-normal mode spectrum is characterized entirely by the black-hole mass and angular momentum and is unique to black holes. In a different theory of gravity, or if the observed radiation arises from a different source (e.g., a neutron star, strange matter or boson star), the spectrum will be inconsistent with that predicted for general relativistic black holes. We give a statistical characterization of the consistency between the noisy observation and the theoretical predictions of general relativity and a demonstration, through simulation, of the effectiveness of the test for strong sources

  15. Black holes a laboratory for testing strong gravity

    CERN Document Server

    Bambi, Cosimo

    2017-01-01

    This textbook introduces the current astrophysical observations of black holes, and discusses the leading techniques to study the strong gravity region around these objects with electromagnetic radiation. More importantly, it provides the basic tools for writing an astrophysical code and testing the Kerr paradigm. Astrophysical black holes are an ideal laboratory for testing strong gravity. According to general relativity, the spacetime geometry around these objects should be well described by the Kerr solution. The electromagnetic radiation emitted by the gas in the inner part of the accretion disk can probe the metric of the strong gravity region and test the Kerr black hole hypothesis. With exercises and examples in each chapter, as well as calculations and analytical details in the appendix, the book is especially useful to the beginners or graduate students who are familiar with general relativity while they do not have any background in astronomy or astrophysics.

  16. Barriers to HIV testing for migrant black Africans in Western Europe.

    Science.gov (United States)

    Fakoya, I; Reynolds, R; Caswell, G; Shiripinda, I

    2008-07-01

    Migrant black Africans are disproportionately affected by HIV in Western Europe; we discuss the barriers to HIV testing for sub-Saharan migrants, with particular emphasis on the UK and the Netherlands. Cultural, social and structural barriers to testing, such as access to testing and care, fear of death and disease and fear of stigma and discrimination in the community, can be identified. Lack of political will, restrictive immigration policies and the absence of African representation in decision-making processes are also major factors preventing black Africans from testing. HIV testing strategies need to be grounded in outreach and community mobilisation, addressing fear of diagnosis, highlighting the success of treatment and tackling HIV-related stigma among black African migrant communities.

  17. Ethnic Comparisons in HIV Testing Attitudes, HIV Testing, and Predictors of HIV Testing Among Black and White College Students.

    Science.gov (United States)

    Moore, Melanie P; Javier, Sarah J; Abrams, Jasmine A; McGann, Amanda Wattenmaker; Belgrave, Faye Z

    2017-08-01

    This study's primary aim was to examine ethnic differences in predictors of HIV testing among Black and White college students. We also examined ethnic differences in sexual risk behaviors and attitudes toward the importance of HIV testing. An analytic sample of 126 Black and 617 White undergraduatestudents aged 18-24 were analyzed for a subset of responses on the American College Health Association-National College Health Assessment II (ACHA-NCHA II) (2012) pertaining to HIV testing, attitudes about the importance of HIV testing, and sexual risk behaviors. Predictors of HIV testing behavior were analyzed using logistic regression. t tests and chi-square tests were performed to access differences in HIV test history, testing attitudes, and sexual risk behaviors. Black students had more positive attitudes toward testing and were more likely to have been tested for HIV compared to White students. A greater number of sexual partners and more positive HIV testing attitudes were significant predictors of HIV testing among White students, whereas relationship status predicted testing among Black students. Older age and history of ever having sex were significant predictors of HIV testing for both groups. There were no significant differences between groups in number of sexual partners or self-reports in history of sexual experience (oral, vaginal, or anal). Factors that influence HIV testing may differ across racial/ethnic groups. Findings support the need to consider racial/ethnic differences in predictors of HIV testing during the development and tailoring of HIV testing prevention initiatives targeting college students.

  18. Antioxidant and Antibacterial Activity of Kombucha Beverages Prepared using Banana Peel, Common Nettles and Black Tea Infusions

    Directory of Open Access Journals (Sweden)

    Ali Ebrahimi Pure

    2016-03-01

    Full Text Available Backgrounds and Objective: Kombucha is a several thousand years old traditional fermented beverage originated from East. While black tea infusion is the common substrate for preparing kombucha, other herbal infusions can be applied for this reason too. Common medicinal herbs or even waste herbal materials, like banana peel, could be suitable substrates for preparing kombucha analogues. In this study, kombuchas were fermented using nettles leaf and banana peel infusions. Materials and Methods: Herbal infusions were fermented by kombucha fungi. Folin-Ciocalteu assay was performed to evaluate total phenolic contents; Free radical scavenging activity was evaluated using 2,2-diphenyl-1-picrylhydrazyl. Disk diffusion method was performed to measure inhibitory activity against testing bacteria. All data were statistically analyzed by ANOVA test at significant level of p≤0.05. Results and Conclusion: Black tea contained highest amount of phenolics (530.5 ppm gallic acid equivalent and fermentation decomposed approximately 50% of phenolic contents to 265.5 ppm while phenolic content of nettles infusion and fermented beverage were 173 gAE and 188 gAE respectively and for banana peel, 136.5 gAE and 155 gAE; it indicated increase of phenolic contents due to fermentation that may be cause of protein contents of nettles and banana peel gone under fermentation by lactic acid bacteria. Fermented beverage of three herbs had higher antioxidant potent than infusions. Kombucha from banana peel showed the highest antioxidant activity by inhibiting 94.62% of DPPH. While antioxidant activity of fermented beverages of black tea and nettles leaf were more related to their acetic acid content, it was found that a considerable part of antioxidant activity of banana peel kombucha was due to other acids and phenolics. No antibacterial activity was observed from either of samples. Banana peel, as a waste herbal material, and nettles leaf are good ingredients for being

  19. Fuel cell testing of Pt–Ru catalysts supported on differently prepared and pretreated carbon nanotubes

    International Nuclear Information System (INIS)

    Tokarz, Wojciech; Lota, Grzegorz; Frackowiak, Elzbieta; Czerwiński, Andrzej; Piela, Piotr

    2013-01-01

    Proton-exchange membrane fuel cell (PEMFC) testing of Pt–Ru catalysts supported on differently prepared multiwall carbon nanotube (MCNT) supports was performed to elucidate the influence of the different supports on the operating characteristics of the catalysts under real direct methanol fuel cell (DMFC) anode and H 2 -PEMFC anode conditions. The MCNTs were either thin, entangled or thick, disentangled. Pretreatment of the MCNTs was also done and it was either high-temperature KOH etching or annealing (graphitization). The performance of the catalysts was compared against the performance of a commercial Pt–Ru catalyst supported on a high-surface-area carbon black. Among the different MCNT supports, the graphitized, entangled support offered the best performance in all tests, which was equal to the performance of the commercial catalyst, despite the MCNT catalyst layer was ca. 2.2 times thicker than the carbon black catalyst layer. Even for an MCNT catalyst layer, which was almost 7 times thicker than the carbon black catalyst layer, the transport limitations were not prohibitive. This confirmed the expected potential of nanotube supports for providing superior reactant transport properties of the PEMFC catalyst layers

  20. School accountability and the black-white test score gap.

    Science.gov (United States)

    Gaddis, S Michael; Lauen, Douglas Lee

    2014-03-01

    Since at least the 1960s, researchers have closely examined the respective roles of families, neighborhoods, and schools in producing the black-white achievement gap. Although many researchers minimize the ability of schools to eliminate achievement gaps, the No Child Left Behind Act (NCLB) increased pressure on schools to do so by 2014. In this study, we examine the effects of NCLB's subgroup-specific accountability pressure on changes in black-white math and reading test score gaps using a school-level panel dataset on all North Carolina public elementary and middle schools between 2001 and 2009. Using difference-in-difference models with school fixed effects, we find that accountability pressure reduces black-white achievement gaps by raising mean black achievement without harming mean white achievement. We find no differential effects of accountability pressure based on the racial composition of schools, but schools with more affluent populations are the most successful at reducing the black-white math achievement gap. Thus, our findings suggest that school-based interventions have the potential to close test score gaps, but differences in school composition and resources play a significant role in the ability of schools to reduce racial inequality. Copyright © 2013 Elsevier Inc. All rights reserved.

  1. Stability of fragrance patch test preparations applied in test chambers.

    Science.gov (United States)

    Mowitz, M; Zimerson, E; Svedman, C; Bruze, M

    2012-10-01

    Petrolatum patch test preparations are for practical reasons often applied in test chambers in advance, several hours or even days before the patient is tested. As many fragrance compounds are volatile it may be suspected that petrolatum preparations applied in test chambers are not stable over time. To investigate the stability of petrolatum preparations of the seven chemically defined components in the fragrance mix (FM I) when stored in test chambers. Samples of petrolatum preparations applied in test chambers stored at room temperature and in a refrigerator for between 4 and 144 h were analysed using liquid chromatographic methods. The concentration decreased by ≥ 20% within 8 h in four of seven preparations stored in Finn chambers at room temperature. When stored in a refrigerator only the preparation of cinnamal had decreased by ≥ 20% within 24 h. The stability of preparations of cinnamal stored in IQ chambers with a plastic cover was slightly better, but like the preparations applied in Finn chambers, the concentration decreased by ≥ 20% within 4 h at room temperature and within 24 h in a refrigerator. Cinnamal and cinnamyl alcohol were found to be more stable when analysed as ingredients in FM I compared with when analysed in individual preparations. Within a couple of hours several fragrance allergens evaporate from test chambers to an extent that may affect the outcome of the patch test. Application to the test chambers should be performed as close to the patch test occasion as possible and storage in a refrigerator is recommended. © 2012 The Authors. BJD © 2012 British Association of Dermatologists.

  2. Communication Between Middle SES Black Women and Healthcare Providers About HIV Testing.

    Science.gov (United States)

    Fray, Niasha A; Caldwell, Kia Lilly

    2017-01-01

    This article explores the impact of patient and healthcare provider communication (PPC) on the HIV testing behaviors of middle socioeconomic status (SES) Black women in North Carolina. We explore how PPC about STIs and HIV (or the lack thereof) affects the provision of STI/HIV testing by either confirming the need for middle SES Black women to test routinely or potentially deterring women from feeling they need to be tested. After conducting 15 qualitative interviews with middle SES Black women between 25 and 45 years of age, we uncovered the role of patient self-advocacy in promoting HIV testing among middle SES Black women when they communicate with their healthcare providers. We discuss the importance of healthcare providers engaging their middle SES Black female patients in routine discussions about sexual health and sexual risk reduction, regardless of providers' perceptions of their potential STI/HIV risk. We recommend including SES as a variable in data collection and research in order to better understand how social class, race, and gender affect sexual health behavior and the provision of STI and HIV/AIDS prevention to diverse populations. Copyright © 2016 National Medical Association. Published by Elsevier Inc. All rights reserved.

  3. Correlation between rheological and mechanical properties of black PE100 compounds – Effect of carbon black masterbatch

    Directory of Open Access Journals (Sweden)

    G. Pircheraghi

    2017-08-01

    Full Text Available Black PE100 compounds were prepared using a co-rotating twin screw extruder by addition of carbon black masterbatches containing 35–40 wt% carbon black and different polymer carriers to a pipe grade PE100 material with bimodal molecular weight distribution. Different properties of carbon black masterbatches and PE100 black compounds were evaluated using thermal, rheological and mechanical tests. Rheological results indicated an inverse correlation between melt flow index (MFI of masterbatch samples and storage modulus, complex viscosity and shear viscosity of black compounds, while flow instabilities of compounds were also postponed to higher shear rates. TGA indicated that masterbatch with highest value of MFI contained highest amount of low molecular weight lubricants which resulted in inhibition of strain hardening behavior in tensile test of its respective black compound unlike all other samples, reflecting possible suppressing of its long term resistance to slow crack growth. This behavior is attributable to facilitated crystallization and chain folding of longer chains in the presence of low molecular weight lubricants in this sample and consequently formation of thicker lamellas as confirmed by DSC, hence lowering density of entanglements in amorphous area and inhibition of strain hardening.

  4. Preparation and characterization of dopamine-decorated hydrophilic carbon black

    Energy Technology Data Exchange (ETDEWEB)

    Zhu Lijun; Lu Yonglai [State Key Laboratory of Organic-Inorganic Composites, Beijing University of Chemical Technology, Beijing 100029 (China); Key Laboratory of Beijing City on Preparation and Processing of Novel Polymer Materials, Beijing 100029 (China); Wang Yiqing [State Key Laboratory of Organic-Inorganic Composites, Beijing University of Chemical Technology, Beijing 100029 (China); Key Laboratory of Carbon Fiber and Functional Polymers, Ministry of Education, Beijing 100029 (China); Zhang Liqun [State Key Laboratory of Organic-Inorganic Composites, Beijing University of Chemical Technology, Beijing 100029 (China); Key Laboratory of Beijing City on Preparation and Processing of Novel Polymer Materials, Beijing 100029 (China); Wang Wencai, E-mail: wangw@mail.buct.edu.cn [State Key Laboratory of Organic-Inorganic Composites, Beijing University of Chemical Technology, Beijing 100029 (China); Key Laboratory of Carbon Fiber and Functional Polymers, Ministry of Education, Beijing 100029 (China)

    2012-05-01

    Inspired by the bio-adhesive proteins secreted by mussels for attachment to almost all wet substrates, a facile method involving oxidative polymerization of dopamine was proposed to prepare highly hydrophilic carbon black (CB) particles. A self-assembled polydopamine (PDA) ad-layer was formed via the oxidative polymerization of dopamine on the surface of CB simply by dipping the CB into an alkaline dopamine solution and mildly stirring at room temperature. The process is simple, controllable, and environment-friendly. The surface composition and structure of the CB were characterized by X-ray photoelectron spectroscopy (XPS) and Fourier transform infrared spectroscopy (FTIR). The surface morphology of the CB was observed by scanning electron microscopy (SEM) and transmission electron microscopy (TEM). The results showed that the PDA ad-layer was successfully deposited on the CB surfaces. The PDA-functionalized CB (CB-PDA) gave a stable colloidal dispersion in water. Contact angle measurement results indicated that the hydrophilicity of CB was significantly improved after dopamine modification. TGA results confirmed that the modified CB maintained good heat resistance. The method provided a facile route to prepare hydrophilic CB having terminal hydroxyl groups.

  5. End-preparation assessments and tests for compounded sterile preparations.

    Science.gov (United States)

    McElhiney, Linda F

    2013-01-01

    Outsourcing has become a necessity to obtain sterile products that are currently on backorder. Because of the expense of outsourcing sterile compounding, pharmacy leadership in health systems are now considering the option of insourcing and batch preparing compounded sterile preparations, which can be a viable option for a health system. It can significantly decrease drug-spending costs, and the pharmacy has a complete record of the compounding process. The key to preparing high-quality, safe, sterile preparations and meeting United States Pharmacopeia standards is end-preparation assessments and tests.

  6. Destroying charged black holes in higher dimensions with test particles

    Science.gov (United States)

    Wu, Bin; Liu, Weiyang; Tang, Hao; Yue, Rui-Hong

    2017-07-01

    A possible way to destroy the Tangherlini Reissner-Nordström black hole is discussed in the spirit of Wald’s gedanken experiment. By neglecting radiation and self force effects, the absorbing condition and destruction condition of the test point particle which is capable of destroying the black hole are obtained. We find that it is impossible to challenge the weak cosmic censorship for an initially extremal black hole in all dimensions. Instead, it is shown that the near extremal black hole will turn into a naked singularity in this particular process, in which case the allowed range of the particle’s energy is very narrow. The result indicates that the self-force effects may well change the outcome of the calculation.

  7. Selective coating for solar panels. [using black chrome and black nickel

    Science.gov (United States)

    Mcdonald, G. E. (Inventor)

    1977-01-01

    The energy absorbing properties of solar heating panels are improved by depositing a black chrome coating of controlled thickness on a specially prepared surface of a metal substrate. The surface is prepared by depositing a dull nickel on the substrate, and the black chrome is plated on this low emittance surface to a thickness between 0.5 micron and 2.5 microns.

  8. Preparing for CLIC tests

    CERN Multimedia

    Laurent Guiraud

    1999-01-01

    The Canon 5 undergoes first brazing for preparation in the CLIC study at the CLIC Test Facility 2 (CTF2). This will test injection for a proposed linear collider that will further explore discoveries made at the LHC. Electric fields in the canon will boost electrons into the acceleration fields of the collider.

  9. Aroma changes of black tea prepared from methyl jasmonate treated tea plants*

    Science.gov (United States)

    Shi, Jiang; Wang, Li; Ma, Cheng-ying; Lv, Hai-peng; Chen, Zong-mao; Lin, Zhi

    2014-01-01

    Methyl jasmonate (MeJA) was widely applied in promoting food quality. Aroma is one of the key indicators in judging the quality of tea. This study examined the effect of exogenous MeJA treatment on tea aroma. The aroma components in black tea prepared from MeJA-treated fresh tea leaves were extracted using headspace solid-phase microextraction (HS-SPME) and were analyzed using gas chromatography-mass spectrometry (GC-MS) and GC-olfactometry (GC-O). Forty-five volatile compounds were identified. The results revealed that the MeJA-treated black tea had higher levels of terpene alcohols and hexenyl esters than the untreated tea. Moreover, several newly components, including copaene, cubenol, and indole, were induced by the MeJA treatment. The activities of polyphenol oxidase and β-glucosidase in fresh tea leaves changed after the MeJA treatment. Quantitative real-time polymerase chain reaction (qRT-PCR) analysis indicated that the gene expression levels of polyphenol oxidase and β-primeverosidase were upregulated by two and three folds, respectively, by the MeJA treatment (Ptea was clearly improved. PMID:24711352

  10. Testing the Binary Black Hole Nature of a Compact Binary Coalescence.

    Science.gov (United States)

    Krishnendu, N V; Arun, K G; Mishra, Chandra Kant

    2017-09-01

    We propose a novel method to test the binary black hole nature of compact binaries detectable by gravitational wave (GW) interferometers and, hence, constrain the parameter space of other exotic compact objects. The spirit of the test lies in the "no-hair" conjecture for black holes where all properties of a Kerr black hole are characterized by its mass and spin. The method relies on observationally measuring the quadrupole moments of the compact binary constituents induced due to their spins. If the compact object is a Kerr black hole (BH), its quadrupole moment is expressible solely in terms of its mass and spin. Otherwise, the quadrupole moment can depend on additional parameters (such as the equation of state of the object). The higher order spin effects in phase and amplitude of a gravitational waveform, which explicitly contains the spin-induced quadrupole moments of compact objects, hence, uniquely encode the nature of the compact binary. Thus, we argue that an independent measurement of the spin-induced quadrupole moment of the compact binaries from GW observations can provide a unique way to distinguish binary BH systems from binaries consisting of exotic compact objects.

  11. Barriers to HIV testing for migrant black Africans in Western Europe

    NARCIS (Netherlands)

    Fakoya, A.; Reynolds, R.; Caswell, G.; Shiripinda, I.

    2008-01-01

    Migrant black Africans are disproportionately affected by HIV in Western Europe; we discuss the barriers to HIV testing for sub-Saharan migrants, with particular emphasis on the UK and the Netherlands. Cultural, social and structural barriers to testing, such as access to testing and care, fear of

  12. Urban Preparation: Young Black Men Moving from Chicago's South Side to Success in Higher Education

    Science.gov (United States)

    Warren, Chezare A.

    2017-01-01

    Chezare A. Warren chronicles the transition of a cohort of young Black males from Urban Prep Charter Academy for Young Men to their early experiences in higher education. A rich and closely observed account of a mission-driven school and its students, "Urban Preparation" makes a significant contribution to our understanding of how young…

  13. Spinning test particles in the field of a black hole

    Energy Technology Data Exchange (ETDEWEB)

    Tod, K P; de Felice, F [Padua Univ. (Italy); Calvani, M [Padua Univ. (Italy). Istituto di Astronomia

    1976-08-11

    It is studied the motion of spinning test bodies in the gravitational field of a rotating black hole, confining the examination of the pole-dipole approximation and of the special case of motion in the equatorial plane with the spin vector perpendicular to it. The study also provides the locus of the turning points for the equatorial orbits and also the exact limits of validity of the pole-dipole approximation for any given set of particle parameters. The innermost stable circular orbits are studied in details, and it is found that opposite spinning accreting particles are separated by the gravitational field of the black hole and that the fraction of energy ''at infinity'' which can be extracted when the particle spin is opposite to that of the black hole can be as high as 100%.

  14. The current ability to test theories of gravity with black hole shadows

    Science.gov (United States)

    Mizuno, Yosuke; Younsi, Ziri; Fromm, Christian M.; Porth, Oliver; De Laurentis, Mariafelicia; Olivares, Hector; Falcke, Heino; Kramer, Michael; Rezzolla, Luciano

    2018-04-01

    Our Galactic Centre, Sagittarius A*, is believed to harbour a supermassive black hole, as suggested by observations tracking individual orbiting stars1,2. Upcoming submillimetre very-long baseline interferometry images of Sagittarius A* carried out by the Event Horizon Telescope collaboration (EHTC)3,4 are expected to provide critical evidence for the existence of this supermassive black hole5,6. We assess our present ability to use EHTC images to determine whether they correspond to a Kerr black hole as predicted by Einstein's theory of general relativity or to a black hole in alternative theories of gravity. To this end, we perform general-relativistic magnetohydrodynamical simulations and use general-relativistic radiative-transfer calculations to generate synthetic shadow images of a magnetized accretion flow onto a Kerr black hole. In addition, we perform these simulations and calculations for a dilaton black hole, which we take as a representative solution of an alternative theory of gravity. Adopting the very-long baseline interferometry configuration from the 2017 EHTC campaign, we find that it could be extremely difficult to distinguish between black holes from different theories of gravity, thus highlighting that great caution is needed when interpreting black hole images as tests of general relativity.

  15. Explaining the black-white gap in cognitive test scores: Toward a theory of adverse impact.

    Science.gov (United States)

    Cottrell, Jonathan M; Newman, Daniel A; Roisman, Glenn I

    2015-11-01

    In understanding the causes of adverse impact, a key parameter is the Black-White difference in cognitive test scores. To advance theory on why Black-White cognitive ability/knowledge test score gaps exist, and on how these gaps develop over time, the current article proposes an inductive explanatory model derived from past empirical findings. According to this theoretical model, Black-White group mean differences in cognitive test scores arise from the following racially disparate conditions: family income, maternal education, maternal verbal ability/knowledge, learning materials in the home, parenting factors (maternal sensitivity, maternal warmth and acceptance, and safe physical environment), child birth order, and child birth weight. Results from a 5-wave longitudinal growth model estimated on children in the NICHD Study of Early Child Care and Youth Development from ages 4 through 15 years show significant Black-White cognitive test score gaps throughout early development that did not grow significantly over time (i.e., significant intercept differences, but not slope differences). Importantly, the racially disparate conditions listed above can account for the relation between race and cognitive test scores. We propose a parsimonious 3-Step Model that explains how cognitive test score gaps arise, in which race relates to maternal disadvantage, which in turn relates to parenting factors, which in turn relate to cognitive test scores. This model and results offer to fill a need for theory on the etiology of the Black-White ethnic group gap in cognitive test scores, and attempt to address a missing link in the theory of adverse impact. (c) 2015 APA, all rights reserved).

  16. 40 CFR 205.57-3 - Test vehicle preparation.

    Science.gov (United States)

    2010-07-01

    ... 40 Protection of Environment 24 2010-07-01 2010-07-01 false Test vehicle preparation. 205.57-3... PROGRAMS TRANSPORTATION EQUIPMENT NOISE EMISSION CONTROLS Medium and Heavy Trucks § 205.57-3 Test vehicle preparation. (a) Prior to the official test, the test vehicle selected in accordance with § 205-57-2 shall not...

  17. Preparation and application of tea to a tritium performance testing programme

    International Nuclear Information System (INIS)

    Daka, J. N.; Moodie, G.; Dinardo, A.; Kramer, G. H.

    2012-01-01

    A simple, but novel technique, for adjusting steeps of black tea to produce fluids, which are visually and spectroscopically similar to urine, has been developed at the National Calibration Reference Centre for Bioassay and In Vivo Monitoring in Canada. The method uses scans of absorbance versus wavelength, in the UV-VIS range (200-800 nm) to select diluted tea steeps that simulate urine. Tea solutions (1 and 10 %) were spiked with tritium and distributed to laboratories for performance testing (PT). The PT exercise was done as in a regular bioassay programme. The results showed that all samples satisfied the pass/fail conditions of the S-106 standard of the Canadian Nuclear Safety Commission, suggesting that adjusted tea successfully simulated urine for the tritium PT programmes. Also, since unlike urine whose use may increase the probability of contaminating and transmitting diseases (e.g. hepatitis C), tea is a safer alternative. When needed, it can readily be prepared for the laboratories. (authors)

  18. Inhibition of raw starch digestion by one glucoamylase preparation from black Aspergillus at high enzyme concentration

    Energy Technology Data Exchange (ETDEWEB)

    Saka, B C; Veda, S

    1981-09-01

    Raw starch digestion by glucoamylase I (Ab. G-I) preparation from black Aspergillus was inhibited significantly at relatively high concentration of the enzyme. The properties of this enzyme were studied together with those of another glucoamylase I (Nor. G-I), also from black Aspergillus. The two glucoamylases do not differ so much in their physico-chemical properties such as molecular weight, pH and thermal stability, pH and temperature optimum, substrate specificity, debranching activity, isoelectric point etc. The adsorption rate of both enzymes on raw starch increased by the increase of enzyme concentration. The raw starch digestion rate by adsorbed Ab. G-I, however, was decreased with the increase of concentration of enzyme whereas the same was increased in case of Nor. G-I. The inhibitory effect was weaker at 60 deg. Celcius or above. (Refs. 11).

  19. Recruiting and Retaining Black Teachers to Work in Urban Schools

    Directory of Open Access Journals (Sweden)

    Brian R. Evans

    2013-09-01

    Full Text Available The purpose of this article is to examine teacher preparation from the perspective of novice Black teachers. While all teachers, regardless of race, can be trained to be effective teachers of Black students, Black teachers can be more adept at motivating and engaging students of color. Six Black teachers were interviewed to determine their experiences during teacher preparation and induction. Findings revealed the teachers believed their programs were high quality and prepared them well to teach in urban spaces, but some expressed concern about the swift immersion into the classroom.

  20. Statistical Tests Black swans or dragon-kings? A simple test for deviations from the power law★

    Science.gov (United States)

    Janczura, J.; Weron, R.

    2012-05-01

    We develop a simple test for deviations from power law tails. Actually, from the tails of any distribution. We use this test - which is based on the asymptotic properties of the empirical distribution function - to answer the question whether great natural disasters, financial crashes or electricity price spikes should be classified as dragon-kings or `only' as black swans.

  1. Adapting the Get Yourself Tested Campaign to Reach Black and Latino Sexual-Minority Youth.

    Science.gov (United States)

    Garbers, Samantha; Friedman, Allison; Martinez, Omar; Scheinmann, Roberta; Bermudez, Dayana; Silva, Manel; Silverman, Jen; Chiasson, Mary Ann

    2016-09-01

    Culturally appropriate efforts are needed to increase sexually transmitted disease (STD) testing and care among Black and Latino sexual-minority youth, who are at high risk for STDs. Get Yourself Tested, a national testing campaign, has demonstrated success among youth, but it has yet to be assessed for relevance or impact among this population. This effort included (1) formative and materials-testing research through focus groups; (2) adaptation of existing Get Yourself Tested campaign materials to be more inclusive of Black and Latino sexual-minority youth; (3) a 3-month campaign in four venues of New York City, promoting STD testing at events and through mobile testing and online and social media platforms; (4) process evaluation of outreach activities; and (5) an outcome evaluation of testing at select campaign venues, using a preexperimental design. During the 3-month campaign period, the number of STD tests conducted at select campaign venues increased from a comparable 3-month baseline period. Although testing uptake through mobile vans remained low in absolute numbers, the van drew a high-prevalence sample, with positivity rates of 26.9% for chlamydia and 11.5% for gonorrhea. This article documents the process and lessons learned from adapting and implementing a local campaign for Black and Latino sexual-minority youth. © 2016 Society for Public Health Education.

  2. Preferences for HIV test characteristics among young, Black Men Who Have Sex With Men (MSM) and transgender women: Implications for consistent HIV testing

    Science.gov (United States)

    Frye, Victoria; Hirshfield, Sabina; Chiasson, Mary Ann; Lucy, Debbie; Usher, DaShawn; McCrossin, Jermaine; Greene, Emily; Koblin, Beryl

    2018-01-01

    Background Promoting consistent HIV testing is critical among young, Black Men Who Have Sex With Men (MSM) and transgender women who are overrepresented among new HIV cases in the United States. New HIV test options are available, including mobile unit testing, one-minute testing, at home or self-testing and couples HIV testing and counseling (CHTC). In the context of these newer options, the objective of this study was to explore whether and how preferences for specific characteristics of the tests acted as barriers to and/or facilitators of testing in general and consistent testing specifically among young Black MSM and transgender women aged 16 to 29. Methods We conducted 30 qualitative, semi-structured, in-depth interviews with young, Black, gay, bisexual or MSM and transgender women in the New York City metropolitan area to identify preferences for specific HIV tests and aspects of HIV testing options. Participants were primarily recruited from online and mobile sites, followed by community-based, face-to-face recruitment strategies to specifically reach younger participants. Thematic coding was utilized to analyze the qualitative data based on a grounded theoretical approach. Results We identified how past experiences, perceived test characteristics (e.g., accuracy, cost, etc.) and beliefs about the “fit” between the individual, and the test relate to preferred testing methods and consistent testing. Three major themes emerged as important to preferences for HIV testing methods: the perceived accuracy of the test method, venue characteristics, and lack of knowledge or experience with the newer testing options, including self-testing and CHTC. Conclusions These findings suggest that increasing awareness of and access to newer HIV testing options (e.g., free or reduced price on home or self-tests or CHTC available at all testing venues) is critical if these new options are to facilitate increased levels of consistent testing among young, Black MSM and

  3. Preferences for HIV test characteristics among young, Black Men Who Have Sex With Men (MSM) and transgender women: Implications for consistent HIV testing.

    Science.gov (United States)

    Frye, Victoria; Wilton, Leo; Hirshfield, Sabina; Chiasson, Mary Ann; Lucy, Debbie; Usher, DaShawn; McCrossin, Jermaine; Greene, Emily; Koblin, Beryl

    2018-01-01

    Promoting consistent HIV testing is critical among young, Black Men Who Have Sex With Men (MSM) and transgender women who are overrepresented among new HIV cases in the United States. New HIV test options are available, including mobile unit testing, one-minute testing, at home or self-testing and couples HIV testing and counseling (CHTC). In the context of these newer options, the objective of this study was to explore whether and how preferences for specific characteristics of the tests acted as barriers to and/or facilitators of testing in general and consistent testing specifically among young Black MSM and transgender women aged 16 to 29. We conducted 30 qualitative, semi-structured, in-depth interviews with young, Black, gay, bisexual or MSM and transgender women in the New York City metropolitan area to identify preferences for specific HIV tests and aspects of HIV testing options. Participants were primarily recruited from online and mobile sites, followed by community-based, face-to-face recruitment strategies to specifically reach younger participants. Thematic coding was utilized to analyze the qualitative data based on a grounded theoretical approach. We identified how past experiences, perceived test characteristics (e.g., accuracy, cost, etc.) and beliefs about the "fit" between the individual, and the test relate to preferred testing methods and consistent testing. Three major themes emerged as important to preferences for HIV testing methods: the perceived accuracy of the test method, venue characteristics, and lack of knowledge or experience with the newer testing options, including self-testing and CHTC. These findings suggest that increasing awareness of and access to newer HIV testing options (e.g., free or reduced price on home or self-tests or CHTC available at all testing venues) is critical if these new options are to facilitate increased levels of consistent testing among young, Black MSM and transgender women. Addressing perceptions of

  4. Preferences for HIV test characteristics among young, Black Men Who Have Sex With Men (MSM and transgender women: Implications for consistent HIV testing.

    Directory of Open Access Journals (Sweden)

    Victoria Frye

    Full Text Available Promoting consistent HIV testing is critical among young, Black Men Who Have Sex With Men (MSM and transgender women who are overrepresented among new HIV cases in the United States. New HIV test options are available, including mobile unit testing, one-minute testing, at home or self-testing and couples HIV testing and counseling (CHTC. In the context of these newer options, the objective of this study was to explore whether and how preferences for specific characteristics of the tests acted as barriers to and/or facilitators of testing in general and consistent testing specifically among young Black MSM and transgender women aged 16 to 29.We conducted 30 qualitative, semi-structured, in-depth interviews with young, Black, gay, bisexual or MSM and transgender women in the New York City metropolitan area to identify preferences for specific HIV tests and aspects of HIV testing options. Participants were primarily recruited from online and mobile sites, followed by community-based, face-to-face recruitment strategies to specifically reach younger participants. Thematic coding was utilized to analyze the qualitative data based on a grounded theoretical approach.We identified how past experiences, perceived test characteristics (e.g., accuracy, cost, etc. and beliefs about the "fit" between the individual, and the test relate to preferred testing methods and consistent testing. Three major themes emerged as important to preferences for HIV testing methods: the perceived accuracy of the test method, venue characteristics, and lack of knowledge or experience with the newer testing options, including self-testing and CHTC.These findings suggest that increasing awareness of and access to newer HIV testing options (e.g., free or reduced price on home or self-tests or CHTC available at all testing venues is critical if these new options are to facilitate increased levels of consistent testing among young, Black MSM and transgender women. Addressing

  5. 40 CFR 205.160-2 - Test sample selection and preparation.

    Science.gov (United States)

    2010-07-01

    ... 40 Protection of Environment 24 2010-07-01 2010-07-01 false Test sample selection and preparation... sample selection and preparation. (a) Vehicles comprising the sample which are required to be tested... maintained in any manner unless such preparation, tests, modifications, adjustments or maintenance are part...

  6. TESTING THE NO-HAIR THEOREM WITH OBSERVATIONS IN THE ELECTROMAGNETIC SPECTRUM. II. BLACK HOLE IMAGES

    International Nuclear Information System (INIS)

    Johannsen, Tim; Psaltis, Dimitrios

    2010-01-01

    According to the no-hair theorem, all astrophysical black holes are fully described by their masses and spins. This theorem can be tested observationally by measuring (at least) three different multipole moments of the spacetimes of black holes. In this paper, we analyze images of black holes within a framework that allows us to calculate observables in the electromagnetic spectrum as a function of the mass, spin, and, independently, the quadrupole moment of a black hole. We show that a deviation of the quadrupole moment from the expected Kerr value leads to images of black holes that are either prolate or oblate depending on the sign and magnitude of the deviation. In addition, there is a ring-like structure around the black hole shadow with a diameter of ∼10 black hole masses that is substantially brighter than the image of the underlying accretion flow and that is independent of the astrophysical details of accretion flow models. We show that the shape of this ring depends directly on the mass, spin, and quadrupole moment of the black hole and can be used for an independent measurement of all three parameters. In particular, we demonstrate that this ring is highly circular for a Kerr black hole with a spin a ∼< 0.9 M, independent of the observer's inclination, but becomes elliptical and asymmetric if the no-hair theorem is violated. Near-future very long baseline interferometric observations of Sgr A* will image this ring and may allow for an observational test of the no-hair theorem.

  7. Testing holographic conjectures of complexity with Born-Infeld black holes

    Energy Technology Data Exchange (ETDEWEB)

    Tao, Jun; Wang, Peng; Yang, Haitang [Sichuan University, Center for Theoretical Physics, College of Physical Science and Technology, Chengdu (China)

    2017-12-15

    In this paper, we use Born-Infeld black holes to test two recent holographic conjectures of complexity, the ''Complexity = Action'' (CA) duality and ''Complexity = Volume 2.0'' (CV) duality. The complexity of a boundary state is identified with the action of the Wheeler-deWitt patch in CA duality, while this complexity is identified with the spacetime volume of the WdW patch in CV duality. In particular, we check whether the Born-Infeld black holes violate the generalized Lloyd bound: C ≤ (2)/(πℎ) [(M - QΦ) - (M - QΦ){sub gs}], where gs stands for the ground state for a given electrostatic potential. We find that the ground states are either some extremal black hole or regular spacetime with nonvanishing charges. For Born-Infeld black holes, we compute the action growth rate at the late-time limit and obtain the complexities in CA and CV dualities. Near extremality, the generalized Lloyd bound is violated in both dualities. Near the charged regular spacetime, this bound is satisfied in CV duality but violated in CA duality. When moving away from the ground state on a constant potential curve, the generalized Lloyd bound tends to be saturated from below in CA duality. (orig.)

  8. Tensile-Creep Test Specimen Preparation Practices of Surface Support Liners

    Science.gov (United States)

    Guner, Dogukan; Ozturk, Hasan

    2017-12-01

    Ground support has always been considered as a challenging issue in all underground operations. Many forms of support systems and supporting techniques are available in the mining/tunnelling industry. In the last two decades, a new polymer based material, Thin Spray-on Liner (TSL), has attained a place in the market as an alternative to the current areal ground support systems. Although TSL provides numerous merits and has different application purposes, the knowledge on mechanical properties and performance of this material is still limited. In laboratory studies, since tensile rupture is the most commonly observed failure mechanism in field applications, researchers have generally studied the tensile testing of TSLs with modification of American Society for Testing and Materials (ASTM) D-638 standards. For tensile creep testing, specimen preparation process also follows the ASTM standards. Two different specimen dimension types (Type I, Type IV) are widely preferred in TSL tensile testing that conform to the related standards. Moreover, molding and die cutting are commonly used specimen preparation techniques. In literature, there is a great variability of test results due to the difference in specimen preparation techniques and practices. In this study, a ductile TSL product was tested in order to investigate the effect of both specimen preparation techniques and specimen dimensions under 7-day curing time. As a result, ultimate tensile strength, tensile yield strength, tensile modulus, and elongation at break values were obtained for 4 different test series. It is concluded that Type IV specimens have higher strength values compared to Type I specimens and moulded specimens have lower results than that of prepared by using die cutter. Moreover, specimens prepared by molding techniques have scattered test results. Type IV specimens prepared by die cutter technique are suggested for preparation of tensile test and Type I specimens prepared by die cutter technique

  9. Testing The ‘Black Swan Effect’ on Croatian Stock Market Between 2000 and 2013

    OpenAIRE

    Radman Peša, Anita; Brajković, Ana

    2015-01-01

    We tested the economic activity and stock exchange of Croatia as a new country of European Union (EU) in order to investigate the ‘Black Swan effect’ from 2000 to 2013. The empirical findings obtained in application of OLS methodology and Chow breaking point test provide evidence and show that resignation of the Croatian ex-Prime Minister did lead country successfully to EU. Also, ‘The Black Swan’ event, being unpredictable and having huge impact on political and economic environm...

  10. Preparation and characterization of Au/CeO{sub 2}-Al{sub 2}O{sub 3} monoliths

    Energy Technology Data Exchange (ETDEWEB)

    Gawel, Bartlomiej; Lambrechts, Kalle [Ugelstad Laboratory, Department of Chemical Engineering, Norwegian University of Science and Technology (NTNU), N-7491 Trondheim (Norway); Oye, Gisle, E-mail: gisle.oye@chemeng.ntnu.no [Ugelstad Laboratory, Department of Chemical Engineering, Norwegian University of Science and Technology (NTNU), N-7491 Trondheim (Norway)

    2012-05-15

    Highlights: Black-Right-Pointing-Pointer A facile method for preparing Au/CeO{sub 2}-Al{sub 2}O{sub 3} monoliths with hierarchical porosity. Black-Right-Pointing-Pointer Continuous-flow testing of the monoliths in liquid-phase oxidation of glucose. Black-Right-Pointing-Pointer Increased catalytic activity in the presence of cerium oxide (stirred-batch tests). - Abstract: Porous CeO{sub 2}-Al{sub 2}O{sub 3} monoliths with hierarchical pore structure were prepared by mixing boehmite particles with solutions containing different amounts of cerium chloride and aluminum nitrate. The monoliths were functionalized with gold nanoparticles using the incipient wetness method. The resulting materials were characterized by X-ray diffraction, nitrogen sorption, mercury porosimetry, UV-vis spectroscopy and transmission electron microscopy. The catalysts were tested in liquid phase glucose oxidation, comparing continuously stirred batch reactor and continuous-flow fix-bed reactor setups.

  11. Black Perceptions of the Mayor: An Empirical Test.

    Science.gov (United States)

    Foster, Lorn S.

    1978-01-01

    During the past ten years Blacks have increased their participation in the urban political process. In a few urban areas, such as Newark and Detroit, Blacks constitute an electoral majority and have elected Black mayors. (Author/RLV)

  12. Testing the black hole "no-hair" hypothesis

    CERN Document Server

    Cardoso, Vitor

    2016-01-01

    Black holes in General Relativity are very simple objects. This property, that goes under the name of "no-hair," has been refined in the last few decades and admits several versions. The simplicity of black holes makes them ideal testbeds of fundamental physics and of General Relativity itself. Here we discuss the no-hair property of black holes, how it can be measured in the electromagnetic or gravitational window, and what it can possibly tell us about our universe.

  13. Testing Black Market vs. Official PPP: A Pooled Mean Group Estimation Approach

    OpenAIRE

    Goswami, Gour Gobinda; Hossain, Mohammad Zariab

    2013-01-01

    Testing purchasing power parity (PPP) using black market exchange rate data has gained popularity in recent times. It is claimed that black market exchange rate data more often support the PPP than the official exchange rate data. In this study, to assess both the long run stability of exchange rate and the short run dynamics, we employ Pooled Mean Group (PMG) Estimation developed by Pesaran et al. (1999) on eight groups of countries based on different criteria. Using the famous Reinhart and ...

  14. Few-layer black phosphorus nanoparticles.

    Science.gov (United States)

    Sofer, Zdenek; Bouša, Daniel; Luxa, Jan; Mazanek, Vlastimil; Pumera, Martin

    2016-01-28

    Herein, black phosphorus quantum dots and nanoparticles of a few layer thickness were prepared and characterized using STEM, AFM, dynamic light scattering, X-ray photoelectron spectroscopy, X-ray diffraction, Raman spectroscopy and photoluminescence. Impact electrochemistry of the induvidual black phosphorus nanoparticles allows their size determination. The centrifugation of colloidal black phosphorus nanoparticles allowed separation of quantum dots with sizes up to 15 nm. These black phosphorus nanoparticles exhibit a large band gap and are expected to find a wide range of applications from semiconductors to biomolecule tags. The use of black phosphorus nanoparticles for vapour sensing was successfully demonstrated.

  15. White holes and eternal black holes

    International Nuclear Information System (INIS)

    Hsu, Stephen D H

    2012-01-01

    We investigate isolated white holes surrounded by vacuum, which correspond to the time reversal of eternal black holes that do not evaporate. We show that isolated white holes produce quasi-thermal Hawking radiation. The time reversal of this radiation, incident on a black hole precursor, constitutes a special preparation that will cause the black hole to become eternal. (paper)

  16. Separation followed by direct SERS detection of explosives on a novel black silicon multifunctional nanostructured surface prepared in a microfluidic channel

    DEFF Research Database (Denmark)

    Talian, Ivan; Hübner, Jörg

    2013-01-01

    The article describes the multifunctionality of a novel black silicon (BS) nanostructured surface covered with a thin layer of noble metal prepared in the a microfluidic channel. It is focused on the separation properties of the BS substrate with direct detection of the separated analytes utilizing...

  17. Testing General Relativity with the Reflection Spectrum of the Supermassive Black Hole in 1H0707-495.

    Science.gov (United States)

    Cao, Zheng; Nampalliwar, Sourabh; Bambi, Cosimo; Dauser, Thomas; García, Javier A

    2018-02-02

    Recently, we have extended the x-ray reflection model relxill to test the spacetime metric in the strong gravitational field of astrophysical black holes. In the present Letter, we employ this extended model to analyze XMM-Newton, NuSTAR, and Swift data of the supermassive black hole in 1H0707-495 and test deviations from a Kerr metric parametrized by the Johannsen deformation parameter α_{13}. Our results are consistent with the hypothesis that the spacetime metric around the black hole in 1H0707-495 is described by the Kerr solution.

  18. What Black Women Know and Want to Know About Counseling and Testing for BRCA1/2.

    Science.gov (United States)

    Adams, Inez; Christopher, Juleen; Williams, Karen Patricia; Sheppard, Vanessa B

    2015-06-01

    Black women are just as likely to have hereditary breast cancer mutations as White women, yet their participation in genetic counseling and testing is substantially lower. This study sought to describe Black women's awareness and perceptions of BRCA1/2 testing and to identify barriers and motivators to seeking BRCA1/2 services. Fifty intercept interviews were conducted with Black women in public places (a professional women's basketball game, a grocery store, a faith-based community event, and the waiting area at a breast care clinic) in Washington, DC. More than half of the women (54%) were aware that genetic tests to determine risk for certain breast and ovarian cancers exist, but the majority (88%) had never heard of BRCA1/2, specifically. After hearing a description of BRCA1/2 genetic markers, 82% stated that they would agree to BRCA1/2 testing if it was offered to them. Perceived advantages of testing included cancer prevention and the ability to share information with family members. Perceived disadvantages included emotional distress associated with identification of the mutation and the potential misuse of results to deny healthcare or employment. Physician recommendation, self-care, and known family history were among the motivators for testing. Women listed possible media and venues for intervention. In spite of low rates of BRCA1/2 testing in the Black community, women in this sample were open to the idea. Interventions that address barriers and include cultural tailoring are necessary.

  19. 40 CFR 1065.405 - Test engine preparation and maintenance.

    Science.gov (United States)

    2010-07-01

    ... has undergone a stabilization step (or in-use operation). If the engine has not already been... 40 Protection of Environment 32 2010-07-01 2010-07-01 false Test engine preparation and...) AIR POLLUTION CONTROLS ENGINE-TESTING PROCEDURES Engine Selection, Preparation, and Maintenance § 1065...

  20. A massive binary black-hole system in OJ 287 and a test of general relativity.

    Science.gov (United States)

    Valtonen, M J; Lehto, H J; Nilsson, K; Heidt, J; Takalo, L O; Sillanpää, A; Villforth, C; Kidger, M; Poyner, G; Pursimo, T; Zola, S; Wu, J-H; Zhou, X; Sadakane, K; Drozdz, M; Koziel, D; Marchev, D; Ogloza, W; Porowski, C; Siwak, M; Stachowski, G; Winiarski, M; Hentunen, V-P; Nissinen, M; Liakos, A; Dogru, S

    2008-04-17

    Tests of Einstein's general theory of relativity have mostly been carried out in weak gravitational fields where the space-time curvature effects are first-order deviations from Newton's theory. Binary pulsars provide a means of probing the strong gravitational field around a neutron star, but strong-field effects may be best tested in systems containing black holes. Here we report such a test in a close binary system of two candidate black holes in the quasar OJ 287. This quasar shows quasi-periodic optical outbursts at 12-year intervals, with two outburst peaks per interval. The latest outburst occurred in September 2007, within a day of the time predicted by the binary black-hole model and general relativity. The observations confirm the binary nature of the system and also provide evidence for the loss of orbital energy in agreement (within 10 per cent) with the emission of gravitational waves from the system. In the absence of gravitational wave emission the outburst would have happened 20 days later.

  1. Orion Ammonia Boiler System Preflight Test Preparations

    Science.gov (United States)

    Levitt, Julia L.

    2017-01-01

    The Environmental Controls and Life Support Systems (ECLSS) branch at Kennedy Space Center (KSC) is currently undergoing preparations for ground testing of the Orion Multi-Purpose Crew Vehicle (MPCV) to prepare its subsystems for EM-1 (Exploration Mission-1). EM-1, Orions second unmanned flight, is a three-week long lunar mission during which the vehicle will complete a 6-day retrograde lunar orbit before returning to Earth. This paper focuses on the work done during the authors 16-week internship with the Mechanical Engineering Branch of KSCs Engineering Directorate. The authors project involved assisting with the preparations for testing the Orion MPCVs ammonia boiler system. The purpose of the ammonia boiler system is to keep the spacecraft sufficiently cool during the reentry portion of its mission, from service module (SM) separation to post-landing. This system is critical for keeping both the spacecraft (avionics and electronics) and crew alive during reentry, thus a successful test of the system is essential to the success of EM-1. XXXX The author was able to draft a detailed outline of the procedure for the ammonia system functional test. More work will need to be done on the vehicle power-up and power-down portions of the procedure, but the ammonia system testing portion of the procedure is thorough and includes vehicle test configurations, vehicle commands, and GSE. The author was able to compile a substantial list of questions regarding the ammonia system functional test with the help of her mentors. A significant number of these questions were answered in the teleconferences with Lockheed Martin.

  2. Black oil hydrate behavior : a comparison study of testing techniques : SINTEF Wheel and Multicell

    Energy Technology Data Exchange (ETDEWEB)

    Lund, A.; Hjarbo, K.W. [SINTEF Material and Chemistry, Trondheim (Norway); Larsen, R.; Straume, E.O.; Hoiland, S. [SINTEF Petroleum Research, Trondheim (Norway); Bracey, J.T. [BHP Billiton, Houston, TX (United States)

    2008-07-01

    SINTEF has developed a high pressure Multicell system to quickly screen possible inhibitor candidates for black oil systems in high pressure cells and loops. The hydrate self inhibiting properties of a black oil system were evaluated for gas/water and gas/water/oil systems at different water cuts. The oil system was then retested in a fluid flow loop system (Wheel). Different low dosage hydrate inhibitors (LDHI) were then screened in the Multicell system. The most promising inhibitors were tested further in the Wheel system. This paper presented the experimental results of these tests. The Multicell screening method allows 48 parallel low-volume samples to be compared simultaneously. The Wheel is suitable for more thorough testing of large-volume samples at harsh experimental conditions. Black oil samples were tested in this study using both techniques. Experiments were conducted to simulate shut-in and restart situations in a production line at field conditions. Both uninhibited oil and LDHI additives were tested. The Multicell was used to identify the critical water cut limit for uninhibited oil, and for screening the performance of the inhibitor for a large number of LDHIs at relevant conditions. The results from both testing techniques were found to be in good agreement. Both identified the same critical water cut limit. The Multicell technique was shown to be valuable for fast screening, testing and optimization of experimental conditions. However, the Wheel is needed for testing relevant flow behaviour of the systems. 1 ref., 4 tabs., 5 figs.

  3. Carbon black nanoparticles film electrode prepared by using substrate-induced deposition approach

    Energy Technology Data Exchange (ETDEWEB)

    Svegl, Irena Grabec; Bele, Marjan [National Institute of Chemistry, P.O. Box 660, SI-1001 Ljubljana (Slovenia); Ogorevc, Bozidar [National Institute of Chemistry, P.O. Box 660, SI-1001 Ljubljana (Slovenia)], E-mail: bogorevc@ki.si

    2008-11-03

    A new type of carbon film electrode, composed of a thin layer of tightly packed carbon black (CB) nanoparticles deposited onto a gelatin-covered indium tin oxide/glass support using the surface-induced deposition (SID) approach, is presented. Some parameters of the novel SID method were optimized and the surface image and functionalization of the investigated carbon black film electrode (CBFE) was inspected by employing scanning electron microscopy and infrared spectroscopy. A cyclic voltammetry (CV) study was conducted in which the electron-transfer kinetics and CBFE interfacial characteristics were evaluated employing several selected reference redox systems, such as [Ru(NH{sub 3}){sub 6}]{sup 3+/2+}, [Fe(CN){sub 6}]{sup 3-/4-} and Fe{sup 3+/2+} in aqueous, and ferrocene/ferrocenium in acetonitrile media. CV recordings were also performed in order to compare the electrochemical behavior of the CBFE with that of some well-known and established bare carbon-based electrodes. In order to confirm the validity of the CB film preparation method, the electroanalytical performance of the proposed CBFE was examined by carrying out linear sweep voltammetry of ascorbic acid (AA), anodic stripping square-wave voltammetry of Cu(II) in acidic medium, and amperometric measurements of hydrogen peroxide under flow injection conditions. The sensing characteristics of the novel carbon film electrode, demonstrated in this preliminary study, comprise: (i) a wide working potential window ranging from +1.0 to -1.3 V (depending on the solution pH), (ii) a wide applicable pH range (at least from 2 to 12), (iii) low voltammetric background (<5 {mu}A cm{sup -2}), (iv) a satisfactory linear voltammetric and amperometric response (r{sup 2} > 0.99) to various analytes, (v) good reproducibility (for example, r.s.d. of 2% in amperometric detection of H{sub 2}O{sub 2} and r.s.d. of 8.5% for electrode-to-electrode CV runs), and (vi) stable and fast current response (at least 100 CV runs with

  4. Test case preparation using a prototype

    OpenAIRE

    Treharne, Helen; Draper, J.; Schneider, Steve A.

    1998-01-01

    This paper reports on the preparation of test cases using a prototype within the context of a formal development. It describes an approach to building a prototype using an example. It discusses how a prototype contributes to the testing activity as part of a lifecycle based on the use of formal methods. The results of applying the approach to an embedded avionics case study are also presented.

  5. Dye-sensitized solar cells fabricated with black raspberry, black carrot and rosella juice

    Science.gov (United States)

    Tekerek, S.; Kudret, A.; Alver, Ü.

    2011-10-01

    In this work, dye sensitized solar cells (DSSC's) were constructed from black raspberry ( Rubus Ideaus), black carrot ( Daucuscarota L.) and rosella juice ( Hibiscus Sabdariffa L.). In order to fabricate a DSSC the fluorine-doped tin (IV) oxide (FTO) thin films obtained by using spray pyrolysis technique were used as a substrate. TiO2 films on FTO layers were prepared by doctor-blading technique. Platinum-coated counter electrode and liquid Iodide/Iodine electrolyte solution were used to fabricate DSSC's. The efficiencies of solar cells produced with black carrot, rosella and black raspberry juice were calculated as 0.25%, 0.16% and 0.16% respectively, under a sunny day in Kahramanmaraş-Turkey.

  6. Comparison of Refractory Performance in Black Liquor Gasifiers and a Smelt Test System

    International Nuclear Information System (INIS)

    Peascoe, RA

    2001-01-01

    Prior laboratory corrosion studies along with experience at the black liquor gasifier in New Bern, North Carolina, clearly demonstrate that serious material problems exist with the gasifier's refractory lining. Mullite-based and alumina-based refractories used at the New Bern facility suffered significant degradation even though they reportedly performed adequately in smaller scale systems. Oak Ridge National Laboratory's involvement in the failure analysis, and the initial exploration of suitable replacement materials, led to the realization that a simple and reliable, complementary method for refractory screening was needed. The development of a laboratory test system and its suitability for simulating the environment of black liquor gasifiers was undertaken. Identification and characterization of corrosion products were used to evaluate the test system as a rapid screening tool for refractory performance and as a predictor of refractory lifetime. Results from the test systems and pl ants were qualitatively similar

  7. Green preparation using black soybeans extract for graphene-based porous electrodes and their applications in supercapacitors

    Science.gov (United States)

    Chu, Hwei-Jay; Lee, Chi-Young; Tai, Nyan-Hwa

    2016-08-01

    Adopting an in situ construction strategy, green reduction of graphene oxide (GO) and the formation of an open porous structure are simultaneously completed in a one-pot process using an aqueous extract of an anthocyanin-containing plant, black soybean, as a green reducing agent. The reduced GO prepared by the aqueous extract of black soybean (BRGO), and the hydrogel of BRGO are characterized to better understand the nature of BRGO and the evolution of BRGO from GO. Graphene-based porous electrodes for supercapacitors are fabricated using the BRGO hydrogel as a primary material, and the electrochemical performance of the electrodes are further improved when the BRGO porous electrodes are treated in a microwave oven. Owing to the formation of uniformly dispersed nanoparticles on the graphene surface during the microwave treatment, the electrical conductivity of the electrodes improves by four orders of magnitude and the electroactive surface area also increases by over four times, as a consequence, the capacitance is significantly enhanced, reaching a capacitance of 268.4 F g-1 at a charging current of 0.1 A g-1.

  8. Preparing to Test Rover Mobility

    Science.gov (United States)

    2005-01-01

    Rover engineers prepare a mixture of sandy and powdery materials to simulate some difficult Mars driving conditions inside a facility at NASA's Jet Propulsion Laboratory, Pasadena, Calif. The tests in early May 2005 were designed to help plan the best way for the rover Opportunity to drive off of a soft-sand dune that the rover dug itself into the previous week.

  9. SYMPATHETIC NEURAL AND HEMODYNAMIC RESPONSES DURING COLD PRESSOR TEST IN ELDERLY BLACKS AND WHITES

    Science.gov (United States)

    Okada, Yoshiyuki; Jarvis, Sara S.; Best, Stuart A.; Edwards, Jeffrey G.; Hendrix, Joseph M.; Adams-Huet, Beverley; Vongpatanasin, Wanpen; Levine, Benjamin D.; Fu, Qi

    2016-01-01

    The sympathetic response during the cold pressor test (CPT) has been reported to be greater in young blacks than whites, especially in those with a family history of hypertension. Since blood pressure (BP) increases with age, we evaluated whether elderly blacks have greater sympathetic activation during CPT than age-matched whites. BP, heart rate (HR), cardiac output (Qc), and muscle sympathetic nerve activity (MSNA) were measured during supine baseline, 2-min CPT, and 3-min recovery in 47 elderly [68±7 (SD) yrs] volunteers (12 blacks, 35 whites). Baseline BP, HR, Qc, or MSNA did not differ between races. Systolic and diastolic BP (DBP) and HR increased during CPT (all P0.05). Qc increased during CPT and up to 30 sec of recovery in both groups, but was lower in blacks than whites. MSNA increased during CPT in both groups (both P<0.001); the increase in burst frequency was similar between groups, while the increase in total activity was smaller in blacks (P=0.030 for interaction). Peak change (Δ) in DBP was correlated with Δ total activity at 1 min into CPT in both blacks (r=0.78, P=0.003) and whites (r=0.43, P=0.009), while the slope was significantly greater in blacks (P=0.007). Thus, elderly blacks have smaller sympathetic and central hemodynamic (e.g., Qc) responses, but a greater pressor response for a given sympathetic activation during CPT than elderly whites. This response may stem from augmented sympathetic vascular transduction, greater sympathetic activation to other vascular bed(s), and/or enhanced non-adrenergically mediated vasoconstriction in elderly blacks. PMID:27021009

  10. Influence of black tea concentrate on kombucha fermentation

    Directory of Open Access Journals (Sweden)

    Malbaša Radomir V.

    2006-01-01

    Full Text Available Kombucha is cultivated on substrates prepared with different concentrations of black tea and substrate obtained by diluting a substrate with highest concentration of black tea with cold tap water. Qualify of produced beverages is compared with the beverage obtained in traditional fermentation of 1.5 g/L of black tea, sweetened with 70 g/L of sucrose. Inoculation was performed with 10% (v/v of fermentation liquid from previous process, and the fermentation was carried out at 28°C under aerobic conditions, for ten days. Process of fermentation was monitored by following pH, total acids. D-gluconic acid and caffeine content. Beverages obtained in fermentation with diluted black tea concentrate had similar amounts of investigated metabolites compared with traditional one. Use of diluted black tea concentrate as a substrate needs the shorter time for the substrate preparation, which significantly saves energy.

  11. 46 CFR 61.05-5 - Preparation of boilers for inspection and test.

    Science.gov (United States)

    2010-10-01

    ... 46 Shipping 2 2010-10-01 2010-10-01 false Preparation of boilers for inspection and test. 61.05-5... PERIODIC TESTS AND INSPECTIONS Tests and Inspections of Boilers § 61.05-5 Preparation of boilers for... preparing the boilers for the hydrostatic test, they shall be filled with water at not less than 70 °F. and...

  12. Ritual Black Drink consumption at Cahokia

    Science.gov (United States)

    Crown, Patricia L.; Emerson, Thomas E.; Gu, Jiyan; Hurst, W. Jeffrey; Pauketat, Timothy R.; Ward, Timothy

    2012-01-01

    Chemical analyses of organic residues in fragments of pottery from the large site of Cahokia and surrounding smaller sites in Illinois reveal theobromine, caffeine, and ursolic acid, biomarkers for species of Ilex (holly) used to prepare the ritually important Black Drink. As recorded during the historic period, men consumed Black Drink in portions of the American Southeast for ritual purification. This first demonstrated discovery of biomarkers for Ilex occurs in beaker vessels dating between A.D. 1050 and 1250 from Cahokia, located far north of the known range of the holly species used to prepare Black Drink during historic times. The association of Ilex and beaker vessels indicates a sustained ritual consumption of a caffeine-laced drink made from the leaves of plants grown in the southern United States. PMID:22869743

  13. Investigation of the homogeneity of methacrylate allergens in commercially available patch test preparations

    DEFF Research Database (Denmark)

    Mose, Kristian Fredløv; Andersen, Klaus Ejner; Christensen, Lars Porskjaer

    2013-01-01

    The homogeneity of methacrylates in commercial patch test preparations has not yet been investigated. Inhomogeneous patch test preparations may give rise to false-negative or false-positive patch test results in patients suspected of having methacrylate allergy.......The homogeneity of methacrylates in commercial patch test preparations has not yet been investigated. Inhomogeneous patch test preparations may give rise to false-negative or false-positive patch test results in patients suspected of having methacrylate allergy....

  14. GES [Ground Engineering System] test site preparation

    International Nuclear Information System (INIS)

    Cox, C.M.; Mahaffey, M.K.; Miller, W.C.; Schade, A.R.; Toyoda, K.G.

    1987-10-01

    Activities are under way at Hanford to convert the 309 containment building and its associated service wing to a nuclear test facility for the Ground Engineering System (GES) test. Conceptual design is about 80% complete, encompassing facility modifications, a secondary heat transport system, a large vacuum system, a test article cell and handing system, control and data handling systems, and safety andl auxiliary systems. The design makes extensive use of existing equipment to minimize technical risk and cost. Refurbishment of this equipment is 25% complete. Cleanout of some 1000 m 3 of equipment from the earlier reactor test in the facility is 85% complete. An Environmental Assessment was prepared and revised to incorporate Department of Energy (DOE) comments. It is now in the DOE approval chain, where a Finding of No Significant Impact is expected. During the next year, definite design will be well advanced, long-lead procurements will be initiated, construction planning will be completed, an operator training plan will be prepared, and the site (preliminary) safety analysis report will be drafted

  15. Preparation and cellular response of porous A-type carbonated hydroxyapatite nanoceramics

    Energy Technology Data Exchange (ETDEWEB)

    Li Bo, E-mail: Leewave@126.com [Institute of Biomaterials and Living Cell Imaging Technology, School of Metallurgy and Materials Engineering, Chongqing University of Science and Technology, Chongqing 401331 (China) and National Engineering Research Center for Biomaterials, Sichuan University, Chengdu 610064 (China); Liao Xiaoling [Institute of Biomaterials and Living Cell Imaging Technology, School of Metallurgy and Materials Engineering, Chongqing University of Science and Technology, Chongqing 401331 (China); Zheng Li [National Engineering Research Center for Biomaterials, Sichuan University, Chengdu 610064 (China); He Huawei [Department of Prosthodontics, Beijing Stomatological Hospital, Capital Medical University, Beijing, 100050 (China); Wang Hong [National Engineering Research Center for Biomaterials, Sichuan University, Chengdu 610064 (China); Fan Hongsong, E-mail: hsfan68@hotmail.com [National Engineering Research Center for Biomaterials, Sichuan University, Chengdu 610064 (China); Zhang Xingdong [National Engineering Research Center for Biomaterials, Sichuan University, Chengdu 610064 (China)

    2012-05-01

    Microwave sintering using the activated carbon as embedding material was applied in preparation of porous A-type carbonated hydroxyapatite ceramics with nano(nCHA) and submicron (mCHA) structure. By examining the linear shrinkages and the compressive strengths of samples at different temperatures, a suitable microwave sintering temperature was achieved. The microwave sintering method was successfully used to prepare A-type CHA with nano or submicron structure, and the mechanism of the formation of A-type carbonate groups was discussed also. Compared with the samples prepared by the conventional sintering method (mHA), the nCHA bioceramics synthesized by the microwave sintering approach had smaller grain size and more uniform microstructure, and showed a compressive strength similar to the conventional samples. In vitro dissolution test proved that nCHA exhibits better degradation property in comparison to pure HA. Rat osteoblasts were cultured with nCHA, mCHA and mHA to evaluate their biocompatibility, and nCHA showed significant enhancement of cells in attachment, proliferation and differentiation. In conclusion, carbonate groups can be easily introduced to HA crystal structure using the activated carbon as embedding material, and microwave sintering is an effective and simple method in preparing A-type CHA with a nanostructure. Results from this in vitro biological study suggest that porous A-type carbonated hydroxyapatite nanoceramics may be a much better candidate for clinical use in terms of bioactivity. - Highlights: Black-Right-Pointing-Pointer We prepared porous A-type carbonated hydroxyapatite nanoceramics with microwave sintering. Black-Right-Pointing-Pointer We examined physico-chemical characterization and osteoblast response. Black-Right-Pointing-Pointer The nanoceramics have a comparable compressive strength to samples with conventional sintering method. Black-Right-Pointing-Pointer The nanoceramics enhance degradation property, osteoblast

  16. Preparation of HEC Serial Modules for Beam and Cold Tests at CERN in 2000

    CERN Multimedia

    Fischer, A.

    2001-01-01

    Photo 1 - Three mated HEC-1 modules in the clean room, prepared for beam tests. Photo 2 - Three mated HEC-1 modules in the clean room, prepared for beam tests. Photo 3 - Three mated HEC-2 modules in the clean room, prepared for beam tests. Photo 4 - Three mated HEC-2 modules in the clean room, prepared for beam tests. Photo 5 - Close-up of the inner-connecting bars of three mated HEC-2 modules, prepared for beam tests. Photo 6 - Mechanical acceptance tests for HEC serial modules at CERN. Photo 7 - Mechanical acceptance tests for HEC serial modules at CERN. Photo 8 - Four HEC-2 modules in the cryostat, prepared for cold tests.

  17. Preparation of working calibration and test materials: uranyl nitrate solution

    International Nuclear Information System (INIS)

    Yamamura, S.S.; Spraktes, F.W.; Baldwin, J.M.; Hand, R.L.; Lash, R.P.

    1977-05-01

    Reliable working calibration and test materials (WCTMs) are essential to a meaningful analytical measurements quality assurance program. This report describes recommended methods for the preparation of uranyl nitrate solution WCTMs for testing analytical methods, for calibrating methods, and for testing personnel. Uranyl nitrate solution WCTMs can be synthesized from characterized starting materials or prepared from typical plant materials by thorough characterization with reference to primary or secondary reference calibration and test materials (PRCTMs or SRCTMs). Recommended starting materials are described along with detailed procedures for (a) preparing several widely-used types of uranyl nitrate solution WCTMs, (b) packaging the WCTMs, (c) analyzing the WCTMs to establish the reference values or to confirm the synthesis, and (d) statistically evaluating the analytical data to assign reference values and to assess the accuracy of the WCTMs

  18. Teacher Education and Black Male Students in the United States

    Directory of Open Access Journals (Sweden)

    H. Richard Milner

    2013-10-01

    Full Text Available Teacher education programs in the United States (U.S. struggle to prepare teachers to meet the complex needs of elementary and secondary students in public schools - especially those of color, those living in poverty, and those whose first language is not English. In this article, we argue for focused attention on preparing educators to teach African American male students as these students face particular institutional challenges in successfully navigating the U.S. public school system. Drawing from the significant body of research on teacher education and teacher learning for equity and social justice, four Black teacher educators discuss challenges they have faced in classes designed to prepare teachers to teach Black male students. Through an analysis of commonalities in their experiences, they propose means for teacher educators to foster greater understandings of the heterogeneity found among Black male students so that teachers can craft more responsive and responsible educational experiences for Black males.

  19. 21 CFR 660.25 - Potency tests without reference preparations.

    Science.gov (United States)

    2010-04-01

    ... recommended for slide tests or microplate techniques. Blood Grouping Reagent recommended for slide test... Grouping Reagent § 660.25 Potency tests without reference preparations. Products for which Reference Blood Grouping Reagents are not available shall be tested for potency by a method approved by the Director...

  20. HTI CONE PENETROMETER PROBES PREPARATION DEVELOPMENTAL TESTING REPORT

    Energy Technology Data Exchange (ETDEWEB)

    IWATATE, D.F.

    1998-10-26

    The HTI subsurface characterization task will use the Hanford Cone Penetrometer platform (CPP) to deploy soil sensor and sampling probes into the vadose zone/soils around AX-104 during FY-99. This report provides the data and information compiled during vendor field development tests and laboratory/bench checkout. This document is a vendor deliverable item identified in the ARA Statement of Work HNF-2881, Revision 1. This version of the DTR includes to-be-determined items and some incomplete sections. The Rev. 0 is being released to support the concurrent task of procedure preparation and Qualification Test Plan preparation. Revision 1 is planned to contain all data and information.

  1. Testing The ‘Black Swan Effect’ on Croatian Stock Market Between 2000 and 2013

    Directory of Open Access Journals (Sweden)

    Anita Radman Peša

    2016-02-01

    Full Text Available We tested the economic activity and stock exchange of Croatia as a new country of EU in order to investigate the ‘Black Swan effect’ from 2000 to 2013. The empirical findings obtained in application of OLS methodology and Chow breaking point test provide evidence and show that resignation of the Croatian ex Prime Minister lead country successfully to EU, but were also ‘The Black Swan’ event, being unpredictable and having huge impact on political and economic environment in Croatia obtained through CROBEX, Croatian stock exchange indices. Authors conclude that the resignation was connected to one of the first significant cases of corruption in Croatia which has got the negative impact on the economic development of the country in general, dealing at the same time with global recession.

  2. PREPARE: guidelines for planning animal research and testing.

    Science.gov (United States)

    Smith, Adrian J; Clutton, R Eddie; Lilley, Elliot; Hansen, Kristine E Aa; Brattelid, Trond

    2018-04-01

    There is widespread concern about the quality, reproducibility and translatability of studies involving research animals. Although there are a number of reporting guidelines available, there is very little overarching guidance on how to plan animal experiments, despite the fact that this is the logical place to start ensuring quality. In this paper we present the PREPARE guidelines: Planning Research and Experimental Procedures on Animals: Recommendations for Excellence. PREPARE covers the three broad areas which determine the quality of the preparation for animal studies: formulation, dialogue between scientists and the animal facility, and quality control of the various components in the study. Some topics overlap and the PREPARE checklist should be adapted to suit specific needs, for example in field research. Advice on use of the checklist is available on the Norecopa website, with links to guidelines for animal research and testing, at https://norecopa.no/PREPARE .

  3. Study on Formulation Optimization of Black Soybean Paste%黑豆沙配方优化研究

    Institute of Scientific and Technical Information of China (English)

    杨益叶; 周宏胜; 胡花丽; 罗淑芬; 李鹏霞

    2018-01-01

    Black soybean variety "Xindali No. 1" was taken as the raw material of black soybean paste processing, and the optimum formulation of black soybean paste preparation was studied. The sensory quality score of product was used as the evalua-tion criterion. Firstly, sunflower seed oil and white granulated sugar were selected as the best species of oil and sugar for the pro-cessing of black soybean paste. Secondly, the ranges of optimum addition amount of flour, sunflower seed oil and white granulated sugar in black soybean paste were determined based on the results of single-factor tests. Finally, the best proportion of flour, sun-flower seed oil and white granulated sugar in black soybean paste was ascertained through the orthogonal test. The optimum formu-lation of black soybean paste preparation was obtained as follows:50 g black soybean, 20 g white granulated sugar, 15 g sunflow-er seed oil, and 20 g flour. The prepared black soybean paste through the above best formulation had fine and smooth taste, uni-form color and lustre, and unique fragrance without obvious oil leaking out.%针对黑豆沙加工工艺缺乏的现状,以新大粒1号黑豆为原料,进行黑豆沙加工过程主要添加物的配方优化研究.以感官品质评分为标准,首先确定了加工过程中所需的油与糖的最优种类为葵花籽油和白砂糖;基于单因素试验确定面粉、葵花籽油、白砂糖的最佳用量范围,再通过正交试验的方法确定面粉、葵花籽油、白砂糖的最优配比.最终确定新大粒1号黑豆沙最佳配方为:以黑豆质量为基准(100%),添加40%白砂糖,30%葵花籽油,40%面粉.通过该配方制得的黑豆沙口感细腻,色泽均匀,无明显走油现象,具有黑豆沙独特的香味和色泽.

  4. Do Test Design and Uses Influence Test Preparation? Testing a Model of Washback with Structural Equation Modeling

    Science.gov (United States)

    Xie, Qin; Andrews, Stephen

    2013-01-01

    This study introduces Expectancy-value motivation theory to explain the paths of influences from perceptions of test design and uses to test preparation as a special case of washback on learning. Based on this theory, two conceptual models were proposed and tested via Structural Equation Modeling. Data collection involved over 870 test takers of…

  5. The World Ahead: Black Parents Prepare Their Children for Pride and Prejudice.

    Science.gov (United States)

    Morgan, Thomas

    1985-01-01

    Presents interviews with Blacks about past experiences with racial discrimination and the impact of integration and prejudice on their children. Discusses the importance of parental guidance in teaching young Blacks about their cultural heritage and how to cope with prejudice and discrimination. (SA)

  6. Knowledge, group-based medical mistrust, future expectations, and perceived disadvantages of medical genetic testing: perspectives of Black African immigrants/refugees.

    Science.gov (United States)

    Buseh, A; Kelber, S; Millon-Underwood, S; Stevens, P; Townsend, L

    2014-01-01

    Reasons for low participation of ethnic minorities in genetic studies are multifactorial and often poorly understood. Based on published literature, participation in genetic testing is low among Black African immigrants/refugees although they are purported to bear disproportionate disease burden. Thus, research involving Black African immigrant/refugee populations that examine their perspectives on participating in genetic studies is needed. This report examines and describes the knowledge of medical genetics, group-based medical mistrust, and future expectations of genetic research and the influence of these measures on the perceived disadvantages of genetic testing among Black African immigrants/refugees. Using a cross-sectional survey design, a nonprobability sample (n = 212) of Black African immigrants/refugees was administered a questionnaire. Participants ranged in age from 18 to 61 years (mean = 38.91, SD = 9.78). The questionnaire consisted of 5 instruments: (a) sociodemographic characteristics, (b) Knowledge of Medical Genetics scale, (c) Group-Based Medical Mistrust Scale, (d) Future Expectations/Anticipated Consequences of Genetics Research scale, and (e) Perceived Disadvantages of Genetic Testing scale. Participants were concerned that genetic research may result in scientists 'playing God,' interfering with the natural order of life. In multivariate analyses, the perceived disadvantages of genetic testing increased as medical mistrust and anticipated negative impacts of genetic testing increased. Increase in genetic knowledge contributed to a decrease in perceived disadvantages. Our findings suggest that recruitment of Black African immigrants/refugees in genetic studies should address potential low knowledge of genetics, concerns about medical mistrust, the expectations/anticipated consequences of genetic research, and the perceived disadvantages of genetic testing.

  7. G-Tunnel pressurized slot-testing preparations

    International Nuclear Information System (INIS)

    Zimmerman, R.M.; Sifre-Soto, C.; Mann, K.L.; Bellman, R.A. Jr.; Luker, S.; Dodds, D.J.

    1992-04-01

    Designers and analysts of radioactive waste repositories must be able to predict the mechanical behavior of the host rock. Sandia National laboratories elected to conduct a development program on pressurized slot testing and featured (1) development of an improved method to cut slots using a chain saw with diamond-tipped cutters, (2) measurements useful for determining in situ stresses normal to slots, (3) measurements applicable for determining the in situ modulus of deformation parallel to a drift surface, and (4) evaluations of the potentials of pressurized slot strength testing. This report describes the preparations leading to the measurements and evaluations

  8. Gravitational perturbation of the BTZ black hole induced by test particles and weak cosmic censorship in AdS spacetime

    International Nuclear Information System (INIS)

    Rocha, Jorge V.; Cardoso, Vitor

    2011-01-01

    We analyze the gravitational perturbations induced by particles falling into a three dimensional, asymptotically AdS black hole geometry. More specifically, we solve the linearized perturbation equations obtained from the geodesic motion of a ringlike distribution of test particles in the BTZ background. This setup ensures that the U(1) symmetry of the background is preserved. The nonasymptotic flatness of the background raises difficulties in attributing the significance of energy and angular momentum to the conserved quantities of the test particles. This issue is well known but, to the best of our knowledge, has never been addressed in the literature. We confirm that the naive expressions for energy and angular momentum are the correct definitions. Finally, we put an asymptotically AdS version of the weak cosmic censorship to a test: by attempting to overspin the BTZ black hole with test particles it is found that the black hole cannot be spun-up past its extremal limit.

  9. REDSHIFT EVOLUTION IN BLACK HOLE-BULGE RELATIONS: TESTING C IV-BASED BLACK HOLE MASSES

    International Nuclear Information System (INIS)

    Greene, Jenny E.; Peng, Chien Y.; Ludwig, Randi R.

    2010-01-01

    We re-examine claims for redshift evolution in black hole-bulge scaling relations based on lensed quasars. In particular, we refine the black hole (BH) mass estimates using measurements of Balmer lines from near-infrared spectroscopy obtained with Triplespec at Apache Point Observatory. In support of previous work, we find a large scatter between Balmer and UV line widths, both Mg IIλλ2796, 2803 and C IVλλ1548, 1550. There is tentative evidence that C III]λ1909, despite being a blend of multiple transitions, may correlate well with Mg II, although a larger sample is needed for a real calibration. Most importantly, we find no systematic changes in the estimated BH masses for the lensed sample based on Balmer lines, providing additional support to the interpretation that black holes were overly massive compared to their host galaxies at high redshift.

  10. Structural inequalities drive late HIV diagnosis: The role of black racial concentration, income inequality, socioeconomic deprivation, and HIV testing

    Science.gov (United States)

    Ransome, Yusuf; Kawachi, Ichiro; Braunstein, Sarah; Nash, Denis

    2017-01-01

    In the United States, research is limited on the mechanisms that link socioeconomic and structural factors to HIV diagnosis outcomes. We tested whether neighborhood income inequality, socioeconomic deprivation, and black racial concentration were associated with gender-specific rates of HIV in the advanced stages of AIDS (i.e., late HIV diagnosis). We then examined whether HIV testing prevalence and accessibility mediated any of the associations above. Neighborhoods with highest (relative to lowest) black racial concentration had higher relative risk of late HIV diagnosis among men (RR=1.86; 95%CI=1.15, 3.00) and women (RR=5.37; 95% CI=3.16, 10.43) independent of income inequality and socioeconomic deprivation. HIV testing prevalence and accessibility did not significantly mediate the associations above. Research should focus on mechanisms that link black racial concentration to HIV diagnosis outcomes. PMID:27770671

  11. A General Relativistic Null Hypothesis Test with Event Horizon Telescope Observations of the Black Hole Shadow in Sgr A*

    Science.gov (United States)

    Psaltis, Dimitrios; Özel, Feryal; Chan, Chi-Kwan; Marrone, Daniel P.

    2015-12-01

    The half opening angle of a Kerr black hole shadow is always equal to (5 ± 0.2)GM/Dc2, where M is the mass of the black hole and D is its distance from the Earth. Therefore, measuring the size of a shadow and verifying whether it is within this 4% range constitutes a null hypothesis test of general relativity. We show that the black hole in the center of the Milky Way, Sgr A*, is the optimal target for performing this test with upcoming observations using the Event Horizon Telescope (EHT). We use the results of optical/IR monitoring of stellar orbits to show that the mass-to-distance ratio for Sgr A* is already known to an accuracy of ∼4%. We investigate our prior knowledge of the properties of the scattering screen between Sgr A* and the Earth, the effects of which will need to be corrected for in order for the black hole shadow to appear sharp against the background emission. Finally, we explore an edge detection scheme for interferometric data and a pattern matching algorithm based on the Hough/Radon transform and demonstrate that the shadow of the black hole at 1.3 mm can be localized, in principle, to within ∼9%. All these results suggest that our prior knowledge of the properties of the black hole, of scattering broadening, and of the accretion flow can only limit this general relativistic null hypothesis test with EHT observations of Sgr A* to ≲10%.

  12. Feed Preparation for Source of Alkali Melt Rate Tests

    International Nuclear Information System (INIS)

    Stone, M. E.; Lambert, D. P.

    2005-01-01

    The purpose of the Source of Alkali testing was to prepare feed for melt rate testing in order to determine the maximum melt-rate for a series of batches where the alkali was increased from 0% Na 2 O in the frit (low washed sludge) to 16% Na 2 O in the frit (highly washed sludge). This document summarizes the feed preparation for the Source of Alkali melt rate testing. The Source of Alkali melt rate results will be issued in a separate report. Five batches of Sludge Receipt and Adjustment Tank (SRAT) product and four batches of Slurry Mix Evaporator (SME) product were produced to support Source of Alkali (SOA) melt rate testing. Sludge Batch 3 (SB3) simulant and frit 418 were used as targets for the 8% Na 2 O baseline run. For the other four cases (0% Na 2 O, 4% Na 2 O, 12% Na 2 O, and 16% Na 2 O in frit), special sludge and frit preparations were necessary. The sludge preparations mimicked washing of the SB3 baseline composition, while frit adjustments consisted of increasing or decreasing Na and then re-normalizing the remaining frit components. For all batches, the target glass compositions were identical. The five SRAT products were prepared for testing in the dry fed melt-rate furnace and the four SME products were prepared for the Slurry-fed Melt-Rate Furnace (SMRF). At the same time, the impacts of washing on a baseline composition from a Chemical Process Cell (CPC) perspective could also be investigated. Five process simulations (0% Na 2 O in frit, 4% Na 2 O in frit, 8% Na 2 O in frit or baseline, 12% Na 2 O in frit, and 16% Na 2 O in frit) were completed in three identical 4-L apparatus to produce the five SRAT products. The SRAT products were later dried and combined with the complementary frits to produce identical glass compositions. All five batches were produced with identical processing steps, including off-gas measurement using online gas chromatographs. Two slurry-fed melter feed batches, a 4% Na 2 O in frit run (less washed sludge combined with

  13. Black Ink and Red Ink (BIRI) Testing: A Testing Method to Evaluate Both Recall and Recognition Learning in Accelerated Adult-Learning Courses

    Science.gov (United States)

    Rodgers, Joseph Lee; Rodgers, Jacci L.

    2011-01-01

    We propose, develop, and evaluate the black ink-red ink (BIRI) method of testing. This approach uses two different methods within the same test administration setting, one that matches recognition learning and the other that matches recall learning. Students purposively define their own tradeoff between the two approaches. Evaluation of the method…

  14. Test Preparation in the Accountability Era: Toward a Learning-Oriented Approach

    Science.gov (United States)

    Gebril, Atta

    2018-01-01

    The article introduces a learning-oriented approach to test preparation that could help in easing the tension between learning and assessment. The first part of the article discusses the different concepts that are usually used in the context of test preparation. The second section reports on the literature pertaining to the effects of test…

  15. Black Holes and Gravitational Properties of Antimatter

    CERN Document Server

    Hajdukovic, D

    2006-01-01

    We speculate about impact of antigravity (i.e. gravitational repulsion between matter and antimatter) on the creation and emission of particles by a black hole. If antigravity is present a black hole made of matter may radiate particles as a black body, but this shouldn't be true for antiparticles. It may lead to radical change of radiation process predicted by Hawking and should be taken into account in preparation of the attempt to create and study mini black holes at CERN. Gravity, including antigravity is more than ever similar to electrodynamics and such similarity with a successfully quantized interaction may help in quantization of gravity.

  16. Disturbance induced by surface preparation on instrumented indentation test

    International Nuclear Information System (INIS)

    Li, Yugang; Kanouté, Pascale; François, Manuel

    2015-01-01

    Surface preparation, which may induce considerable sample disturbance, plays an important role in instrumented indentation test (IIT). In this study, the sample disturbance (mainly divided into residual stresses and plastic strain) induced by the surface preparation process of instrumented indentation test specimens were investigated with both experimental tests and numerical simulations. Grazing incidence X-ray diffractions (GIXRD) and uniaxial tensile tests were conducted for characterizing the residual stresses and high plastic strain in the top surface layers of a carefully mechanically polished indentation sample, which, in the present work, is made of commercially pure titanium. Instrumented indentation tests and the corresponding finite element simulations were performed as well. For comparison, a reference sample (carefully mechanically polished & electrolytically polished) which represents the raw material was prepared and tested. Results showed that a careful mechanical polishing procedure can effectively reduce the level of residual stresses induced by this process. However, the high plastic strain in the surface region imposed by the polishing process is significant. The induced plastic strain can affect a depth up to 5 µm, which is deeper than the maximum penetration depth h max (3 µm) used for the instrumented indentation tests. In the near surface layer (in the range of depth about 350 nm), the plastic strain levels are fairly high. In the very top layer, the plastic strain was even estimated to reach more than 60%. The simultaneous use of indentation tests and numerical simulations showed that the existence of high plastic strain in the surface region will make the load vs depth (P–h) curve shift upwards, the contact hardness (H) increase and the contact stiffness (S) decrease

  17. Disturbance induced by surface preparation on instrumented indentation test

    Energy Technology Data Exchange (ETDEWEB)

    Li, Yugang, E-mail: yugang.li@utt.fr [Université de Technologie de Troyes (UTT), ICD-LASMIS, UMR CNRS 6281, 12, rue Marie Curie-CS 42060, 10010 Troyes Cedex (France); Kanouté, Pascale, E-mail: pascale.kanoute@onera.fr [Université de Technologie de Troyes (UTT), ICD-LASMIS, UMR CNRS 6281, 12, rue Marie Curie-CS 42060, 10010 Troyes Cedex (France); The French Aerospace Lab (ONERA), DMSM/MCE, 29 avenue de la Division Leclerc-BP 72, F-92322 Chatillon Cedex (France); François, Manuel, E-mail: manuel.francois@utt.fr [Université de Technologie de Troyes (UTT), ICD-LASMIS, UMR CNRS 6281, 12, rue Marie Curie-CS 42060, 10010 Troyes Cedex (France)

    2015-08-26

    Surface preparation, which may induce considerable sample disturbance, plays an important role in instrumented indentation test (IIT). In this study, the sample disturbance (mainly divided into residual stresses and plastic strain) induced by the surface preparation process of instrumented indentation test specimens were investigated with both experimental tests and numerical simulations. Grazing incidence X-ray diffractions (GIXRD) and uniaxial tensile tests were conducted for characterizing the residual stresses and high plastic strain in the top surface layers of a carefully mechanically polished indentation sample, which, in the present work, is made of commercially pure titanium. Instrumented indentation tests and the corresponding finite element simulations were performed as well. For comparison, a reference sample (carefully mechanically polished & electrolytically polished) which represents the raw material was prepared and tested. Results showed that a careful mechanical polishing procedure can effectively reduce the level of residual stresses induced by this process. However, the high plastic strain in the surface region imposed by the polishing process is significant. The induced plastic strain can affect a depth up to 5 µm, which is deeper than the maximum penetration depth h{sub max} (3 µm) used for the instrumented indentation tests. In the near surface layer (in the range of depth about 350 nm), the plastic strain levels are fairly high. In the very top layer, the plastic strain was even estimated to reach more than 60%. The simultaneous use of indentation tests and numerical simulations showed that the existence of high plastic strain in the surface region will make the load vs depth (P–h) curve shift upwards, the contact hardness (H) increase and the contact stiffness (S) decrease.

  18. Playing the Game: Recruiting Black Males in Teaching

    Science.gov (United States)

    Green, Satasha L.; Martin, Darren

    2018-01-01

    The purpose of this comparative study is to ascertain the experiences and perceptions of four Black males enrolled in teacher preparation programs, one at a Predominantly Black Institution (PBI) and three at a Predominantly White Institution (PWI). Findings provide insight for Colleges of Teacher Education to understand the barriers that prevent…

  19. Structural inequalities drive late HIV diagnosis: The role of black racial concentration, income inequality, socioeconomic deprivation, and HIV testing.

    Science.gov (United States)

    Ransome, Yusuf; Kawachi, Ichiro; Braunstein, Sarah; Nash, Denis

    2016-11-01

    In the United States, research is limited on the mechanisms that link socioeconomic and structural factors to HIV diagnosis outcomes. We tested whether neighborhood income inequality, socioeconomic deprivation, and black racial concentration were associated with gender-specific rates of HIV in the advanced stages of AIDS (i.e., late HIV diagnosis). We then examined whether HIV testing prevalence and accessibility mediated any of the associations above. Neighborhoods with highest (relative to lowest) black racial concentration had higher relative risk of late HIV diagnosis among men (RR=1.86; 95%CI=1.15, 3.00) and women (RR=5.37; 95%CI=3.16, 10.43) independent of income inequality and socioeconomic deprivation. HIV testing prevalence and accessibility did not significantly mediate the associations above. Research should focus on mechanisms that link black racial concentration to HIV diagnosis outcomes. Copyright © 2016 Elsevier Ltd. All rights reserved.

  20. Teacher Competency in Classroom Testing, Measurement Preparation, and Classroom Testing Practices.

    Science.gov (United States)

    Newman, Dorothy C.; Stallings, William M.

    An assessment instrument and a questionnaire (Appendices A and B) were developed to determine how well teachers understand classroom testing principles and to gain information on the measurement preparation and classroom practices of teachers. Two hundred ninety-four inservice teachers, grades 1 through 12, from three urban school systems in…

  1. Large-scale preparation of hollow graphitic carbon nanospheres

    Energy Technology Data Exchange (ETDEWEB)

    Feng, Jun; Li, Fu [Key Laboratory for Liquid-Solid Structural Evolution and Processing of Materials, Ministry of Education, Shandong University, Jinan 250061 (China); Bai, Yu-Jun, E-mail: byj97@126.com [Key Laboratory for Liquid-Solid Structural Evolution and Processing of Materials, Ministry of Education, Shandong University, Jinan 250061 (China); State Key laboratory of Crystal Materials, Shandong University, Jinan 250100 (China); Han, Fu-Dong; Qi, Yong-Xin; Lun, Ning [Key Laboratory for Liquid-Solid Structural Evolution and Processing of Materials, Ministry of Education, Shandong University, Jinan 250061 (China); Lu, Xi-Feng [Lunan Institute of Coal Chemical Engineering, Jining 272000 (China)

    2013-01-15

    Hollow graphitic carbon nanospheres (HGCNSs) were synthesized on large scale by a simple reaction between glucose and Mg at 550 Degree-Sign C in an autoclave. Characterization by X-ray diffraction, Raman spectroscopy and transmission electron microscopy demonstrates the formation of HGCNSs with an average diameter of 10 nm or so and a wall thickness of a few graphenes. The HGCNSs exhibit a reversible capacity of 391 mAh g{sup -1} after 60 cycles when used as anode materials for Li-ion batteries. -- Graphical abstract: Hollow graphitic carbon nanospheres could be prepared on large scale by the simple reaction between glucose and Mg at 550 Degree-Sign C, which exhibit superior electrochemical performance to graphite. Highlights: Black-Right-Pointing-Pointer Hollow graphitic carbon nanospheres (HGCNSs) were prepared on large scale at 550 Degree-Sign C Black-Right-Pointing-Pointer The preparation is simple, effective and eco-friendly. Black-Right-Pointing-Pointer The in situ yielded MgO nanocrystals promote the graphitization. Black-Right-Pointing-Pointer The HGCNSs exhibit superior electrochemical performance to graphite.

  2. Test anxiety levels and related factors: students preparing for university exams.

    Science.gov (United States)

    Kurt, Ayse Sonay; Balci, Serap; Kose, Dilek

    2014-11-01

    To assess test anxiety levels and related factors among students preparing for university exams. The descriptive, cross-sectional study was conducted at Istanbul University, Turkey, and comprised students preparing for exams in two private courses for the 2010-11 academic year. Data was collected via an original questionnaire and the Test Anxiety Inventory. SPSS 20 was used for statistical analyses. Of the 1250 students who qualified for the study, the final sample size was 376 (30%). Of them, 210 (55.9%) were females, and 154 (41%) were 18 years old. Students' mean Test Anxiety Inventory scores were 39.44±11.34. Female students' overall test anxiety scores and mean emotionality subscale score were significantly higher than those of their male counterparts. Students whose mothers had an educational attainment between primary school n=170 (45.2%) and a high school diploma n=184 (48.9%), as well as those with four or more siblings n=49 (15%), had significantly higher mean overall Test Anxiety Inventory scores. Among other things, test anxiety is influenced by maternal educational level, type of high school, number of exams, and number of siblings. Preparing a relaxed study environment for students, providing the family monetary or social support, and encouraging participation in social activities are recommendedto decreajb anxiety in students preparing for university exams.

  3. Enzyme-assisted extraction of antioxidative phenols from black current juice press residues (Ribes nigrum)

    DEFF Research Database (Denmark)

    Landbo, Anne-Katrine Regel; Meyer, Anne Boye Strunge

    2001-01-01

    Enzymatic release of phenolic compounds from pomace remaining from black currant (Ribes nigrum) juice production was examined. Treatment with each of the commercial pectinolytic enzyme preparations Grindamyl pectinase, Macer8 FJ, Macer8 R, and Pectinex BE, as well as treatment with Novozym 89 pro...... pomace extracts all exerted a pronounced antioxidant activity against human LDL oxidation in vitro when tested at equimolar phenol concentrations of 7.5-10 muM....... protease, significantly increased plant cell wall breakdown of the pomace. Each of the tested enzyme preparations except Grindamyl pectinase also significantly enhanced the amount of phenols extracted from the pomace. Macer8 FJ and Macer8 R decreased the extraction yields of anthocyanins, whereas Pectinex...

  4. Influence of carbon black distribution on performance of oxide cathodes for Li ion batteries

    International Nuclear Information System (INIS)

    Dominko, Robert; Gaberscek, Miran; Drofenik, Jernej; Bele, Marjan; Jamnik, Janez

    2003-01-01

    The influence of carbon black content and carbon black distribution on performance of oxide-based cathodes, such as LiCoO 2 and LiMn 2 O 4 , is investigated. The electronic conductivity of oxide material/carbon black composites is compared with electrochemical characteristics of the same composites. Uniformity of carbon black distribution in cathode composites is achieved using novel coating technology in cathode preparation. In this technology, the active particles are first pretreated in a gelatin solution. The adsorbed gelatin then controls the deposition of carbon black so that carbon black particles are uniformly distributed in the final composite. The influence of various parameters, such as pH of gelatin, amount of gelatin and concentration of carbon black on the uniformity of carbon black distribution is investigated. It is shown that the conventional technology of cathode preparation yields quite non-uniform distribution of carbon black in cathode material. At the end, we demonstrate that uniformity of carbon black distribution has a crucial impact on reversible capacity, especially at high current densities

  5. A test of the massive binary black hole hypothesis - Arp 102B

    Science.gov (United States)

    Helpern, J. P.; Filippenko, Alexei V.

    1988-01-01

    The emission-line spectra of several AGN have broad peaks which are significantly displaced in velocity with respect to the host galaxy. An interpretation of this effect in terms of orbital motion of a binary black hole predicts periods of a few centuries. It is pointed out here that recent measurements of the masses and sizes of many low-luminosity AGN imply orbital periods much shorter than this. In particular, it is found that the elliptical galaxy Arp 102B is the most likely candidate for observation of radial velocity variations; its period is expected to be about 3 yr. The H-alpha line profile of Arp 102B has been measured for 5 yr without detecting any change in velocity, and it is thus found that a rather restrictive observational test of the massive binary black hole hypothesis already exists, albeit for this one object.

  6. Testing the nature of the supermassive black hole candidate in SgrA* with light curves and images of hot spots

    International Nuclear Information System (INIS)

    Li, Zilong; Kong, Lingyao; Bambi, Cosimo

    2014-01-01

    General relativity makes clear predictions about the spacetime geometry around black holes. In the near future, new facilities will have the capability to explore the metric around SgrA*, the supermassive black hole candidate at the center of our Galaxy, and to open a new window to test the Kerr black hole hypothesis. In this paper, we compute light curves and images associated with compact emission regions (hot spots) orbiting around Kerr and non-Kerr black holes. We study how the analysis of the properties of the radiation emitted by a hot spot can be used to test the Kerr nature of SgrA*. We find that the sole observation of the hot spot light curve can at most constrain a combination of the black hole spin and of possible deviations from the Kerr solution. This happens because the same orbital frequency around a Kerr black hole can be found for a non-Kerr object with a different spin parameter. Second order corrections in the light curve due to the background geometry are typically too small to be identified. While the observation of the hot spot centroid track can potentially bound possible deviations from the Kerr solution, that is out of reach for the near future for the Very Large Telescope Interferometer instrument GRAVITY. The Kerr black hole hypothesis could really be tested in the case of the discovery of a radio pulsar in a compact orbit around SgrA*. Radio observations of such a pulsar would provide precise estimates of the mass and the spin of SgrA*, and the combination of these measurements (probing the weak field) with the hot spot light curve information (probing the strong field) may constrain/find possible deviations from the Kerr solution with quite good precision.

  7. Testing the nature of the supermassive black hole candidate in SgrA* with light curves and images of hot spots

    Energy Technology Data Exchange (ETDEWEB)

    Li, Zilong; Kong, Lingyao; Bambi, Cosimo [Center for Field Theory and Particle Physics and Department of Physics, Fudan University, 200433 Shanghai (China)

    2014-06-01

    General relativity makes clear predictions about the spacetime geometry around black holes. In the near future, new facilities will have the capability to explore the metric around SgrA*, the supermassive black hole candidate at the center of our Galaxy, and to open a new window to test the Kerr black hole hypothesis. In this paper, we compute light curves and images associated with compact emission regions (hot spots) orbiting around Kerr and non-Kerr black holes. We study how the analysis of the properties of the radiation emitted by a hot spot can be used to test the Kerr nature of SgrA*. We find that the sole observation of the hot spot light curve can at most constrain a combination of the black hole spin and of possible deviations from the Kerr solution. This happens because the same orbital frequency around a Kerr black hole can be found for a non-Kerr object with a different spin parameter. Second order corrections in the light curve due to the background geometry are typically too small to be identified. While the observation of the hot spot centroid track can potentially bound possible deviations from the Kerr solution, that is out of reach for the near future for the Very Large Telescope Interferometer instrument GRAVITY. The Kerr black hole hypothesis could really be tested in the case of the discovery of a radio pulsar in a compact orbit around SgrA*. Radio observations of such a pulsar would provide precise estimates of the mass and the spin of SgrA*, and the combination of these measurements (probing the weak field) with the hot spot light curve information (probing the strong field) may constrain/find possible deviations from the Kerr solution with quite good precision.

  8. Preparation and application of steeps of tea as new simulations of urine for the performance testing programme of 14C

    International Nuclear Information System (INIS)

    Daka, J. N.; Moodie, G.; DiNardo, A.; Kramer, G. H.

    2012-01-01

    14 C is one of the radionuclides for which the Canadian Nuclear Safety Commission has developed performance testing programmes (PTPs). During the PTP exercises, clients receive samples of natural urine containing spiked radionuclides, for testing. In these programmes, urine has disadvantages. These include (1) slow collection times from donors, (2) unpleasant smell and (3) potential to transmit diseases. To assist in solving some of these problems, the Canadian National Calibration Reference Centre for Bioassay and In Vivo Monitoring has conducted research with tea solutions, to find simpler, safer and more readily available alternatives to urine. This paper provides a new technique by which steeps of black tea have been successfully prepared for the 14 C PTP. The results of tea solutions compared well with those of urine. It was concluded that tea steeps, of which the spectroscopic and colour quenching properties have been adjusted, do provide appropriate urine simulations, suitable for use in PTPs. (authors)

  9. Antimicrobial activity of chitosan coatings and films against Listeria monocytogenes on black radish.

    Science.gov (United States)

    Jovanović, Gordana D; Klaus, Anita S; Nikšić, Miomir P

    2016-01-01

    The antibacterial activity of chitosan coatings prepared with acetic or lactic acid, as well as of composite chitosan-gelatin films prepared with essential oils, was evaluated in fresh shredded black radish samples inoculated with Listeria monocytogenes ATCC 19115 and L. monocytogenes ATCC 19112 during seven days of storage at 4°C. The chitosan coating prepared with acetic acid showed the most effective antibacterial activity. All tested formulations of chitosan films exhibited strong antimicrobial activity on the growth of L. monocytogenes on black radish, although a higher inhibition of pathogens was achieved at higher concentrations of chitosan. The antimicrobial effect of chitosan films was even more pronounced with the addition of essential oils. Chitosan-gelatin films with thyme essential oils showed the most effective antimicrobial activity. A reduction of 2.4log10CFU/g for L. monocytogenes ATCC 19115 and 2.1log10CFU/g for L. monocytogenes ATCC 19112 was achieved in the presence of 1% chitosan film containing 0.2% of thyme essential oil after 24h of storage. Copyright © 2016 Asociación Argentina de Microbiología. Publicado por Elsevier España, S.L.U. All rights reserved.

  10. 40 CFR 205.171-2 - Test exhaust system sample selection and preparation.

    Science.gov (United States)

    2010-07-01

    ... Systems § 205.171-2 Test exhaust system sample selection and preparation. (a)(1) Exhaust systems... 40 Protection of Environment 24 2010-07-01 2010-07-01 false Test exhaust system sample selection and preparation. 205.171-2 Section 205.171-2 Protection of Environment ENVIRONMENTAL PROTECTION AGENCY...

  11. Black holes and cosmic censorship

    International Nuclear Information System (INIS)

    Hiscock, W.A.

    1979-01-01

    It is widely accepted that the complete gravitational collapse of a body always yields a black hole, and that naked singularities are never produced (the cosmic censorship hypothesis). The local (or strong) cosmic censorship hypothesis states that singularities which are even locally naked (e.g., to an observer inside a black hole) are never produced. This dissertation studies the validity of these two conjectures. The Kerr-Newman metrics describes the black holes only when M 2 greater than or equal to Q 2 + P 2 , where M is the mass of the black hole, a = J/M its specific angular momentum, Q its electric charge, and P its magnetic charge. In the first part of this dissertation, the possibility of converting an extreme Kerr-Newman black hole (M 2 = a 2 + Q 2 + P 2 ) into a naked singularity by the accretion of test particles is considered. The motion of test particles is studied with a large angular momentum to energy ratio, and also test particles with a large charge to energy ratio. The final state is always found to be a black hole if the angular momentum, electric charge, and magnetic charge of the black hole are all much greater than the corresponding angular momentum, electric charge, and magnetic charge of the test particle. In Part II of this dissertation possible black hole interior solutions are studied. The Cauchy horizons and locally naked timelike singularities of the charged (and/or rotating) solutions are contrasted with the spacelike all-encompassing singularity of the Schwarzschild solution. It is determined which portions of the analytic extension of the Reissner-Nordstroem solution are relevant to realistic gravitational collapse

  12. Characterization and Comparison of Photocatalytic Activity Silver Ion doped on TiO2(TiO2/Ag+) and Silver Ion doped on Black TiO2(Black TiO2/Ag+)

    Science.gov (United States)

    Kim, Jin Yi; Sim, Ho Hyung; Song, Sinae; Noh, Yeoung Ah; Lee, Hong Woon; Taik Kim, Hee

    2018-03-01

    Titanium dioxide (TiO2) is one of the representative ceramic materials containing photocatalyst, optic and antibacterial activity. The hydroxyl radical in TiO2 applies to the intensive oxidizing agent, hence TiO2 is suitable to use photocatalytic materials. Black TiO2was prepared through reduction of amorphous TiO2 conducting under H2 which leads to color changes. Its black color is proven that absorbs 100% light across the whole-visible light, drawing enhancement of photocatalytic property. In this study, we aimed to compare the photocatalytic activity of silver ion doped on TiO2(TiO2/Ag+) and silver ion doped on black TiO2(black TiO2/Ag+) under visible light range. TiO2/Ag+ was fabricated following steps. 1) TiO2 was synthesized by a sol-gel method from Titanium tetraisopropoxide (TTIP). 2) Then AgNO3 was added during an aging process step for silver ion doping on the surface of TiO2. Moreover, Black TiO2/Ag+ was obtained same as TiO2/Ag+ except for calcination under H2. The samples were characterized X-ray diffraction (XRD), UV-visible reflectance (UV-vis DRS), and Methylene Blue degradation test. XRD analysis confirmed morphology of TiO2. The band gap of black TiO2/Ag+ was confirmed (2.6 eV) through UV-vis DRS, which was lower than TiO2/Ag+ (2.9 eV). The photocatalytic effect was conducted by methylene blue degradation test. It demonstrated that black TiO2/Ag+ had a photocatalytic effect under UV light also visible light.

  13. The angry black woman: the impact of pejorative stereotypes on psychotherapy with black women.

    Science.gov (United States)

    Ashley, Wendy

    2014-01-01

    In the aftermath of slavery and the resulting social, economic, and political effects, Black women have become the victims of negative stereotyping in mainstream American culture. Such stereotypes include the myth of the angry Black woman that characterizes these women as aggressive, ill tempered, illogical, overbearing, hostile, and ignorant without provocation. Symptoms presented by Black women during mental health treatment may reinforce this myth. However, many of the negative characteristics of the angry Black woman developed in response to external stressors and historical factors. Black women also have a unique experience with and expressions of anger that shape the presenting symptoms interpreted by the mental health clinician. This myth and corresponding negative stereotypes significantly affect Black women intrapsychically, interpersonally, and are likely to influence the efficacy of mental health treatment. Understanding and treatment of Black women in a mental health context should be influenced by the cultural norms and sociopolitical dynamics affecting these clients. Successful mental health treatment requires cultural competence and clinicians who are well prepared to navigate the inherent complexities of culture with clients. Awareness of the angry Black woman mythology, including its genesis, manifestations, and the unique experiences of Black women, may raise the standards of cultural competence for clinicians and provide more successful treatment outcomes in working with this population. A case example illustrates the assiduity essential to practicing in a culturally competent manner. A client is presented from a traditional psychotherapeutic perspective and then viewed through a lens that integrates psychotherapeutic practice with conscious awareness of the mythology and stereotypes impacting Black women. Implications for culturally relevant practice are discussed.

  14. Testing the blazar sequence and black hole mass scaling with BL Lac objects

    NARCIS (Netherlands)

    Plotkin, Richard M.; Markoff, Sera; Anderson, Scott F.; Kelly, Brandon C.; Körding, Elmar; Trager, Scott C.; Romero, Gustavo E.; Sunyaev, Rashid A.; Belloni, Tomaso

    Jets from accreting black holes appear remarkably similar over eight orders of magnitude in black hole mass, with more massive black holes generally launching more powerful jets. For example, there is an observed correlation, termed the fundamental plane of black hole accretion, between black hole

  15. Testing the blazar sequence and black hole mass scaling with BL Lac objects

    NARCIS (Netherlands)

    Plotkin, R.M.; Markoff, S.; Anderson, S.F.; Kelly, B.C.; Körding, E.; Trager, S.C.

    2010-01-01

    Jets from accreting black holes appear remarkably similar over eight orders of magnitude in black hole mass, with more massive black holes generally launching more powerful jets. For example, there is an observed correlation, termed the fundamental plane of black hole accretion, between black hole

  16. HIV testing and burden of HIV infection in black cancer patients in Johannesburg, South Africa: a cross-sectional study.

    Science.gov (United States)

    Sengayi, Mazvita; Babb, Chantal; Egger, Matthias; Urban, Margaret I

    2015-03-18

    HIV infection is a known risk factor for cancer but little is known about HIV testing patterns and the burden of HIV infection in cancer patients. We did a cross-sectional analysis to identify predictors of prior HIV testing and to quantify the burden of HIV in black cancer patients in Johannesburg, South Africa. The Johannesburg Cancer Case-control Study (JCCCS) recruits newly-diagnosed black cancer patients attending public referral hospitals for oncology and radiation therapy in Johannesburg . All adult cancer patients enrolled into the JCCCS from November 2004 to December 2009 and interviewed on previous HIV testing were included in the analysis. Patients were independently tested for HIV-1 using a single ELISA test . The prevalence of prior HIV testing, of HIV infection and of undiagnosed HIV infection was calculated. Multivariate logistic regression models were fitted to identify factors associated with prior HIV testing. A total of 5436 cancer patients were tested for HIV of whom 1833[33.7% (95% CI=32.5-35.0)] were HIV-positive. Three-quarters of patients (4092 patients) had ever been tested for HIV. The total prevalence of undiagnosed HIV infection was 11.5% (10.7-12.4) with 34% (32.0-36.3) of the 1833 patients who tested HIV-positive unaware of their infection. Men >49 years [OR 0.49(0.39-0.63)] and those residing in rural areas [OR 0.61(0.39-0.97)] were less likely to have been previously tested for HIV. Men with at least a secondary education [OR 1.79(1.11-2.90)] and those interviewed in recent years [OR 4.13(2.62 - 6.52)] were likely to have prior testing. Women >49 years [OR 0.33(0.27-0.41)] were less likely to have been previously tested for HIV. In women, having children associated with previous HIV testing. In a study of newly diagnosed black cancer patients in Johannesburg, over a third of HIV-positive patients were unaware of their HIV status. In South Africa black cancer patients should be targeted for opt-out HIV testing.

  17. EMPIRICAL TESTING OF MODIFIED BLACK-SCHOLES OPTION PRICING MODEL FORMULA ON NSE DERIVATIVE MARKET IN INDIA

    Directory of Open Access Journals (Sweden)

    Ambrish Gupta

    2013-01-01

    Full Text Available The main objectives of this paper are to incorporate modification in Black-Scholes option pricing model formula by adding some new variables on the basis of given assumption related to risk-free interest rate, and also shows the calculation process of new risk-free interest rate on the basis of modified variable. This paper also identifies the various situations in empirical testing of modified and original Black-Scholes formula with respect to the market value on the basis of assumed and calculated risk-free interest rate.

  18. Effects of different soil preparation techniques on the Anatolian Black Pine (Pinus nigra Arnold subsp. pallasiana (Lamb. Holmboe regeneration

    Directory of Open Access Journals (Sweden)

    Adil Çalışkan

    2014-07-01

    Full Text Available In this study, the effects of different soil preparation treatments on regeneration of black pine success were examined and some suggestions were given according to the results. Twelve sample plots were randomly set in the research area. The size of each sample plot was 4 m². Sample plots were seeded equally with a total number of 2304 (48 seeds per m2 seeds in April 2012. The number of surviving seedlings was recorded every month from May to November in 2012. Surviving seedlings were recorded again in November 2013 and growths of thirty seedlings which are selected randomly from the all sample plots were examined. It was found that soil treatment with machine was more successful in regeneration at semi-arid regions like Cerkes-Turkey. Plowing equipment as mechanical soil cultivation has more economically advantageous in first years. However, the success and quality of seedlings were better in soil preparation with ripper equipment compared to plowing.

  19. Magnetic charge, black holes, and cosmic censorship

    International Nuclear Information System (INIS)

    Hiscock, W.H.

    1981-01-01

    The possibility of converting a Reissner-Nordstroem black hole into a naked singularity by means of test particle accretion is considered. The dually charged Reissner-Nordstroem metric describes a black hole only when M 2 >Q 2 +P 2 . The test particle equations of motion are shown to allow test particles with arbitrarily large magnetic charge/mass ratios to fall radially into electrically charged black holes. To determine the nature of the final state (black hole or naked singularity) an exact solution of Einstein's equations representing a spherical shell of magnetically charged dust falling into an electrically charged black hole is studied. Naked singularities are never formed so long as the weak energy condition is obeyed by the infalling matter. The differences between the spherical shell model and an infalling point test particle are examined and discussed

  20. Self-sampling kits to increase HIV testing among black Africans in the UK: the HAUS mixed-methods study.

    Science.gov (United States)

    Seguin, Maureen; Dodds, Catherine; Mugweni, Esther; McDaid, Lisa; Flowers, Paul; Wayal, Sonali; Zomer, Ella; Weatherburn, Peter; Fakoya, Ibidun; Hartney, Thomas; McDonagh, Lorraine; Hunter, Rachael; Young, Ingrid; Khan, Shabana; Freemantle, Nick; Chwaula, Jabulani; Sachikonye, Memory; Anderson, Jane; Singh, Surinder; Nastouli, Eleni; Rait, Greta; Burns, Fiona

    2018-04-01

    Timely diagnosis of human immunodeficiency virus (HIV) enables access to antiretroviral treatment, which reduces mortality, morbidity and further transmission in people living with HIV. In the UK, late diagnosis among black African people persists. Novel methods to enhance HIV testing in this population are needed. To develop a self-sampling kit (SSK) intervention to increase HIV testing among black Africans, using existing community and health-care settings (stage 1) and to assess the feasibility for a Phase III evaluation (stage 2). A two-stage, mixed-methods design. Stage 1 involved a systematic literature review, focus groups and interviews with key stakeholders and black Africans. Data obtained provided the theoretical base for intervention development and operationalisation. Stage 2 was a prospective, non-randomised study of a provider-initiated, HIV SSK distribution intervention targeted at black Africans. The intervention was assessed for cost-effectiveness. A process evaluation explored feasibility, acceptability and fidelity. Twelve general practices and three community settings in London. HIV SSK return rate. Stage 1 - the systematic review revealed support for HIV SSKs, but with scant evidence on their use and clinical effectiveness among black Africans. Although the qualitative findings supported SSK distribution in settings already used by black Africans, concerns were raised about the complexity of the SSK and the acceptability of targeting. These findings were used to develop a theoretically informed intervention. Stage 2 - of the 349 eligible people approached, 125 (35.8%) agreed to participate. Data from 119 were included in the analysis; 54.5% (65/119) of those who took a kit returned a sample; 83.1% of tests returned were HIV negative; and 16.9% were not processed, because of insufficient samples. Process evaluation showed the time pressures of the research process to be a significant barrier to feasibility. Other major barriers were

  1. Major-element geochemistry of the Silent Canyon--Black Mountain peralkaline volcanic centers, northwestern Nevada Test Site: applications to an assessment of renewed volcanism

    International Nuclear Information System (INIS)

    Crowe, B.M.; Sargent, K.A.

    1979-01-01

    The Silent Canyon and Black Mountain volcanic centers are located in the northern part of the Nevada Test Site. The Silent Canyon volcanic center is a buried cauldron complex of Miocene age (13 to 15 m.y.). Black Mountain volcanic center is an elliptical-shaped cauldron complex of late Miocene age. The lavas and tuffs of the two centers comprise a subalkaline-peralkaline association. Rock types range from quartz normative subalkaline trachyte and rhyolite to peralkaline commendite. The Gold Flat Member of the Thirsty Canyon Tuff (Black Mountain) is a pantellerite. The major-element geochemistry of the Black Mountain--Silent Canyon volcanic centers differ in the total range and distribution of SiO 2 , contents, the degree of peralkalinity (molecular Na 2 O + K 2 O > Al 2 O 3 ) and in the values of total iron and alumina through the range of rock types. These differences indicate that the suites were unrelated and evolved from differing magma bodies. The Black Mountain volcanic cycle represents a renewed phase of volcanism following cessation of the Timber Mountain--Silent Canyon volcanic cycles. Consequently, there is a small but numerically incalculable probability of recurrence of Black Mountain-type volcanism within the Nevada Test Site region. This represents a potential risk with respect to deep geologic storage of high-level radioactive waste at the Nevada Test Site

  2. Effect of Black Rice Powder Levels on Quality Properties of Emulsion-type Sausage

    OpenAIRE

    Park, Sin-Young; Kim, Hack-Youn

    2016-01-01

    The effects of black rice powder on the quality of sausage were investigated. Samples were prepared with 0% (control), 1%, 3%, and 5% black rice powder. With increasing black rice powder content, the moisture and ash content of sausage increased, while protein content was significantly less than that observed for the control (p

  3. Black to Black

    DEFF Research Database (Denmark)

    Langkjær, Michael Alexander

    2012-01-01

    Pop musicians performing in black stage costume take advantage of cultural traditions relating to matters black. Stylistically, black is a paradoxical color: although a symbol of melancholy, pessimism, and renunciation, black also expresses minimalist modernity and signifies exclusivity (as is hi...

  4. The Properties of SBR/ENR50 Blend Containing Nanoclay/Carbon Black Dual Filler System Cured by Electron Beam

    Directory of Open Access Journals (Sweden)

    Sima Ahmadi-Shooli

    2017-05-01

    Full Text Available Nanocomposites based on an SBR/ENR50 rubber blend with the blend ratio of 50/50 using Cloisite 15A nanoclay (5 and 10 phr and carbon black (20 phr were prepared by melt mixing process. The rubber compounds were crosslinked by electron beam irradiation process at 50 and 100 kGy doses. A reference sample containing carbon black at 35 phr was prepared using a conventional sulphur curing system. The gel content of the samples was specified using gel fraction measurement. The results showed the maximum gel content for the sample having 5 phr nanoclay and 20 phr carbon black. The dynamic mechanical properties, including the storage modulus, loss modulus, and loss factor, of the nanocomposites were evaluated using dynamic mechanical analysis (DMA tests. The results indicated that, in spite of a well dispersed nanoclay in samples containing 10 phr nanoclay and 20 phr carbon black, a minimum loss factor was observed in the sample containing 5 phr nanoclay and 20 phr carbon black at 100 kGy. On the other hand, the storage modulus of the reference sample was found to be higher than that of the sample with 5 phr nanoclay and 20 phr carbon black. The mechanical properties, including the tensile strength, stress at 100%, 200%, and 300% elongation and the percentage of elongation were measured by a tensile machine. The results showed an increase in tensile strength and the stress at different elongations for a sample with 5 phr nanoclay and 20 phr carbon black compared to the reference sample. In the corresponding SEM images of the samples having nanoclay and carbon black irradiated at 100 kGy a significantly higher surface roughness was observed.

  5. What is the impact of commercial test preparation courses on medical examination performance?

    Science.gov (United States)

    McGaghie, William C; Downing, Steven M; Kubilius, Ramune

    2004-01-01

    Commercial test preparation courses are part of the fabric of U.S. medical education. They are also big business with 2,000 sales for 1 firm listed at nearly $250 million. This article systematically reviews and evaluates research published in peer-reviewed journals and in the "grey literature" that addresses the impact of commercial test preparation courses on standardized, undergraduate medical examinations. Thirteen computerized English language databases were searched using 29 search terms and search concepts from their onset to October 1, 2002. Also manually searched was medical education conference proceedings and publications after the end date; and medical education journal editors were contacted about articles accepted for publication, but not yet in print, that were deemed pertinent to this review. Studies that met three criteria were selected: (a) a commercial test preparation course or service was an educational intervention, (b) the outcome variable was one of several standardized medical examinations, and (c) results are published in a peer-reviewed journal or another outlet that insures scholarly scrutiny. The criteria were applied and data extracted by consensus of 2 reviewers. The search identified 11 empirical studies, of which 10 (8 journal articles, 2 unpublished reports) are included in this review. Qualitative data synthesis and tabular presentation of research methods and outcomes are used. The articles and unpublished reports reveal that current research lacks control and rigor; the incremental validity of the commercial courses on medical examination performance, if any, is extremely small; and evidence in support of the courses is weak or nonexistent; almost no details are given about the form and conduct of the commercial test preparation courses; studies are confined to courses in preparation for the Medical College Admission Test, the former National Board of Medical Examiners Part 1, and the United States Medical Licensing Examination

  6. Testing the Kerr black hole hypothesis: Comparison between the gravitational wave and the iron line approaches

    Energy Technology Data Exchange (ETDEWEB)

    Cárdenas-Avendaño, Alejandro [Center for Field Theory and Particle Physics and Department of Physics, Fudan University, 200433 Shanghai (China); Programa de Matemática, Fundación Universitaria Konrad Lorenz, 110231 Bogotá (Colombia); Jiang, Jiachen [Center for Field Theory and Particle Physics and Department of Physics, Fudan University, 200433 Shanghai (China); Bambi, Cosimo, E-mail: bambi@fudan.edu.cn [Center for Field Theory and Particle Physics and Department of Physics, Fudan University, 200433 Shanghai (China); Theoretical Astrophysics, Eberhard-Karls Universität Tübingen, 72076 Tübingen (Germany)

    2016-09-10

    The recent announcement of the detection of gravitational waves by the LIGO/Virgo Collaboration has opened a new window to test the nature of astrophysical black holes. Konoplya & Zhidenko have shown how the LIGO data of GW 150914 can constrain possible deviations from the Kerr metric. In this letter, we compare their constraints with those that can be obtained from accreting black holes by fitting their X-ray reflection spectrum, the so-called iron line method. We simulate observations with eXTP, a next generation X-ray mission, finding constraints much stronger than those obtained by Konoplya & Zhidenko. Our results can at least show that, contrary to what is quite commonly believed, it is not obvious that gravitational waves are the most powerful approach to test strong gravity. In the presence of high quality data and with the systematics under control, the iron line method may provide competitive constraints.

  7. Preparation, characterization and microstructural optimization of a thin {gamma}-alumina membrane on a porous stainless steel substrate

    Energy Technology Data Exchange (ETDEWEB)

    Abedini, Sanam [Department of Mining and Metallurgical Engineering, Amirkabir University of Technology (Tehran Polytechnic), Hafez Street, Tehran (Iran, Islamic Republic of); Parvin, Nader, E-mail: naderparvin@yahoo.com [Department of Mining and Metallurgical Engineering, Amirkabir University of Technology (Tehran Polytechnic), Hafez Street, Tehran (Iran, Islamic Republic of); Ashtari, Parviz [Nuclear Science and Technology Research Institute, Tehran (Iran, Islamic Republic of)

    2012-01-30

    Highlights: Black-Right-Pointing-Pointer A mesoporous {gamma}-Al{sub 2}O{sub 3} membrane was synthesized on conventional {alpha}-Al{sub 2}O{sub 3} substrates. Black-Right-Pointing-Pointer {gamma}-Al{sub 2}O{sub 3} membrane was potential for CO{sub 2} separation at high pressure test conditions. Black-Right-Pointing-Pointer Thus, it was required to provide the membrane layer with more strength. Black-Right-Pointing-Pointer {alpha}-Alumina substrate was substituted with porous stainless steel. Black-Right-Pointing-Pointer A stainless steel supported {alpha}-Al{sub 2}O{sub 3} membrane with better properties was synthesized. - Abstract: In this work, a supported mesoporous (MEP) {gamma}-Al{sub 2}O{sub 3} membrane was synthesized on conventional {alpha}-Al{sub 2}O{sub 3} substrates by sol-gel dip coating process. In the following, the preparation of a novel metallic-ceramic composite membrane was studied, which incorporated desirable properties of both ceramic membrane and porous metallic substrate. For this purpose, mesoporous alumina membrane layer was developed on a porous 316L stainless steel substrate. The substrate was prepared by loose powder sintering and modified by soaking-rolling and fast drying method. The prepared membranes were characterized using scanning electron microscope (SEM), field emission scanning electron microscope (FESEM), X-ray diffractometer (XRD) and N{sub 2}-adsorption/desorption measurements (BET analyses). The results revealed that a defect-free {gamma}-alumina membrane with 2.1 nm average pore size can be produced. Permeation tests with N{sub 2} gas revealed that the stainless steel substrate had 40 times more permeability than conventionally used alumina support. Additionally, single gas permeation of {gamma}-alumina membrane for CO{sub 2} and N{sub 2} was compared. It was observed that CO{sub 2} could be separated from N{sub 2} by the MEP {gamma}-Al{sub 2}O{sub 3} membrane in high pressure permeation condition, where stainless steel

  8. Observational test for the existence of a rotating black hole in Cyg X-1. [Gravitatinal effects, polarization properties

    Energy Technology Data Exchange (ETDEWEB)

    Stark, R F; Connors, P A [Oxford Univ. (UK). Dept. of Astrophysics

    1977-03-31

    It is stated that the degree and plane of linear polarisation of the radiation from Cyg X-1 are being investigated by X-ray satellite experiments. This radiation can be explained as coming from an accretion disk around a black hole, the polarisation of the X-rays being due to electron scattering in the hotter inner regions of the disk. Existing predictions of the polarisation properties, as a function of energy, have been based on a Newtonian approximation, thus neglecting gravitational effects on the rays as they propagate from the surface of the disk to an observer at infinity. Preliminary results are here given of a full general relativistic calculation that shows that gravitational effects completely alter the polarisation properties, and provide a sensitive test of the existence of a black hole. It is found that for a rapidly rotating black hole the general relativistic effects on the polarisation properties are an order of magnitude greater than for a slowly rotating black hole, or for a neutron star. The degree of linear polarisation of the rays as they leave the disk will also differ from the Newtonian value, and gravitational bending of the light will alter the angle at which a ray leaves the surface of the disk. The large general relativistic variation of the polarisation plane with energy is illustrated graphically. The very large general relativistic rotations in the plane of polarisation provide an opportunity for testing the black hole hypothesis for Cyg X-1. In order to observe these effects X-ray satellite experiments will be required with more sensitive polarimetry across a wider energy range than is available at present.

  9. Preparation and testing of plant seed meal-based wood adhesives.

    Science.gov (United States)

    He, Zhongqi; Chapital, Dorselyn C

    2015-03-05

    Recently, the interest in plant seed meal-based products as wood adhesives has steadily increased, as these plant raw materials are considered renewable and environment-friendly. These natural products may serve as alternatives to petroleum-based adhesives to ease environmental and sustainability concerns. This work demonstrates the preparation and testing of the plant seed-based wood adhesives using cottonseed and soy meal as raw materials. In addition to untreated meals, water washed meals and protein isolates are prepared and tested. Adhesive slurries are prepared by mixing a freeze-dried meal product with deionized water (3:25 w/w) for 2 hr. Each adhesive preparation is applied to one end of 2 wood veneer strips using a brush. The tacky adhesive coated areas of the wood veneer strips are lapped and glued by hot-pressing. Adhesive strength is reported as the shear strength of the bonded wood specimen at break. Water resistance of the adhesives is measured by the change in shear strength of the bonded wood specimens at break after water soaking. This protocol allows one to assess plant seed-based agricultural products as suitable candidates for substitution of synthetic-based wood adhesives. Adjustments to the adhesive formulation with or without additives and bonding conditions could optimize their adhesive properties for various practical applications.

  10. Preparation of refractory cermet structures for lithium compatibility testing

    Science.gov (United States)

    Heestand, R. L.; Jones, R. A.; Wright, T. R.; Kizer, D. E.

    1973-01-01

    High-purity nitride and carbide cermets were synthesized for compatability testing in liquid lithium. A process was developed for the preparation of high-purity hafnium nitride powder, which was subsequently blended with tungsten powder or tantalum nitride and tungsten powders and fabricated into 3 in diameter billets by uniaxial hot pressing. Specimens were then cut from the billets for compatability testing. Similar processing techniques were applied to produce hafnium carbide and zirconium carbide cermets for use in the testing program. All billets produced were characterized with respect to chemistry, structure, density, and strength properties.

  11. Morphological, biochemical and sensory characteristics of black mulberry fruits (Morus nigra L.

    Directory of Open Access Journals (Sweden)

    Beáta Stehlíková

    2013-02-01

    Full Text Available This work aimed at the morphological, biochemical, technological and sensorial determination of black mulberry (Morus nigra L. – MN  fruitage and their utilization in the food production branches. For the experimental purposes were selected 50 genotypes of this population grown in the Pukanec surroundings. The medium fruitage weight determined in the selected collection ranged from 7.26 g (MN-1 to 1.42 g (MN-14, fruitage length in a range of 13.51 mm (MN-14 to 29.20 mm (MN-12 and the medium fruitage width  11.88 mm (MN-14 – 21.12 mm (MN-2. The variability of the evaluated traits varried from low to high degree. Juice yield from matured fruitage achieved 62.40 %. From black mulberry fruitages 16 food products were prepared – juice mixed with cream, yoghurt and/or curd (in several proportions and 3 confectionery products. Sensorial analyses showed significant differences among tested products. In the group of confectionery products was generally preferred the cream-mulberry cake. High values of antioxidative activity has been measured in the chocolate cake with a mulberry jam (36.90 – 28.43 %, followed by the cream-mulberry cake (29.78 – 12.71 % and the fresh mulberry juice (30.97 – 20.17 %. The antioxidation activities exerted generally higher values with the samples tested in water, when compared with those prepared in ethanol extract. Based on the gained results 4 genotypes were selected and recommended for the use in practice, as these provided relative high values of tested traits.doi:10.5219/234

  12. Accreting fluids onto regular black holes via Hamiltonian approach

    Energy Technology Data Exchange (ETDEWEB)

    Jawad, Abdul [COMSATS Institute of Information Technology, Department of Mathematics, Lahore (Pakistan); Shahzad, M.U. [COMSATS Institute of Information Technology, Department of Mathematics, Lahore (Pakistan); University of Central Punjab, CAMS, UCP Business School, Lahore (Pakistan)

    2017-08-15

    We investigate the accretion of test fluids onto regular black holes such as Kehagias-Sfetsos black holes and regular black holes with Dagum distribution function. We analyze the accretion process when different test fluids are falling onto these regular black holes. The accreting fluid is being classified through the equation of state according to the features of regular black holes. The behavior of fluid flow and the existence of sonic points is being checked for these regular black holes. It is noted that the three-velocity depends on critical points and the equation of state parameter on phase space. (orig.)

  13. Alcoholic Beverages Obtained from Black Mulberry

    Directory of Open Access Journals (Sweden)

    Jacinto Darias-Martín

    2003-01-01

    Full Text Available Black mulberry (Morus nigra is a fruit not known only for its nutritional qualities and its flavour, but also for its traditional use in natural medicine as it has a high content of active therapeutic compounds. However, this fruit is not widely produced in Spain but some trees are still found growing in the Canary Islands, particularly on the edges of the ravine. The inhabitants of these islands (Tenerife, La Gomera, La Palma, El Hierro and Lanzarote collect the fruit and prepare homemade beverages for medicinal purposes. Numerous authors have reported that type II diabetes mellitus can be controlled by taking a mixture containing black mulberry and water. Apart from that, this fruit has been used for the treatment of mouth, tongue and throat inflammations. In this study we present some characteristics of black mulberry juice (TSS, pH, titratable acidity, citric acid, lactic acid, polyphenols, anthocyanins, the potassium etc. and alcoholic beverages (alcoholic grade, pH, total acidity, volatile acidity, tannins, phenols etc. obtained from black mulberry. Moreover, we have studied the quality of liquors obtained from black mulberry in Canary Islands.

  14. Combustion synthesis: A new approach for preparation of thermoelectric zinc antimonide compounds

    Energy Technology Data Exchange (ETDEWEB)

    Rouessac, F., E-mail: Florence.Rouessac@univ-montp2.fr [Institut Charles Gerhardt Montpellier, UMR 5253 CNRS-UM2-ENSCM-UM1, C2M Universite Montpellier 2, CC 1504 Place Eugene Bataillon, 34095 Montpellier Cedex 5 (France); Ayral, R.-M. [Institut Charles Gerhardt Montpellier, UMR 5253 CNRS-UM2-ENSCM-UM1, C2M Universite Montpellier 2, CC 1504 Place Eugene Bataillon, 34095 Montpellier Cedex 5 (France)

    2012-07-25

    Highlights: Black-Right-Pointing-Pointer Reliable preparation method of thermoelectric materials. Black-Right-Pointing-Pointer Formation of zinc antimonide by the combustion synthesis method is investigated. Black-Right-Pointing-Pointer XRD and Raman spectroscopy as a function of temperature. Black-Right-Pointing-Pointer SHS: a new way for synthesizing thermoelectric materials. - Abstract: Due to the interesting properties of Zn{sub 4}Sb{sub 3} thermoelectric material, a reliable preparation method of this material is required. In this study, the formation of zinc antimonides by the combustion synthesis method is investigated and subjected to characterization using X-ray diffraction and Raman spectroscopy as a function of temperature. The results show that combustion synthesis can be a new way for synthesizing these thermoelectric materials.

  15. Acquisition and preparation of specimens of rock for large-scale testing

    International Nuclear Information System (INIS)

    Watkins, D.J.

    1981-01-01

    The techniques used for acquisition and preparation of large specimens of rock for laboratory testing depend upon the location of the specimen, the type of rock and the equipment available at the sampling site. Examples are presented to illustrate sampling and preparation techniques used for two large cylindrical samples of granitic material, one pervasively fractured and one containing a single fracture

  16. Tests for the existence of black holes through gravitational wave echoes

    Science.gov (United States)

    Cardoso, Vitor; Pani, Paolo

    2017-09-01

    The existence of black holes and spacetime singularities is a fundamental issue in science. Despite this, observations supporting their existence are scarce, and their interpretation is unclear. In this Perspective we outline the case for black holes that has been made over the past few decades, and provide an overview of how well observations adjust to this paradigm. Unsurprisingly, we conclude that observational proof for black holes is, by definition, impossible to obtain. However, just like Popper's black swan, alternatives can be ruled out or confirmed to exist with a single observation. These observations are within reach. In the coming years and decades, we will enter an era of precision gravitational-wave physics with more sensitive detectors. Just as accelerators have required larger and larger energies to probe smaller and smaller scales, more sensitive gravitational-wave detectors will probe regions closer and closer to the horizon, potentially reaching Planck scales and beyond. What may be there, lurking?

  17. A New Business: Redirecting Black Youth from the Illegal Economy

    Science.gov (United States)

    Cox Edmondson, Vickie

    2009-01-01

    Young Black males are an at-risk group for earning a living through illegal activities in the U.S. As with most at-risk groups, concerted efforts have been made to help prepare them to become viable contributors and valued members of society. Anecdotal evidence shows that faculty members have also tried to reach out and influence young Black males…

  18. CDC'S Testing Makes Us Stronger (TMUS) Campaign: Was Campaign Exposure Associated With HIV Testing Behavior Among Black Gay and Bisexual Men?

    Science.gov (United States)

    Habarta, Nancy; Boudewyns, Vanessa; Badal, Hannah; Johnston, Jennie; Uhrig, Jennifer; Green, Donata; Ruddle, Paul; Rosenthal, Jacqueline; Stryker, Jo Ellen

    2017-06-01

    This study assessed exposure among Black gay, bisexual, and other men who have sex with men (BMSM) to a communication campaign, Testing Makes Us Stronger (TMUS), and its association with HIV testing to determine campaign effectiveness. Data from an online survey (N = 3,105) were analyzed using propensity score weight-adjusted logistic regression to examine the effect of exposure on HIV testing. Among BMSM aged 18-44 (n = 702), 43.2% reported TMUS exposure. The majority of those exposed were aged 25-34 (54%), HIV-negative (65%), and had some college education (87%). TMUS exposure was associated with reported increased HIV testing behaviors at 6- and 12-month frequencies. Communication campaigns with clear implementation strategies, focused objectives, and online and event presence can be associated with longer-term outcomes such as HIV testing.

  19. Varying constants, black holes, and quantum gravity

    International Nuclear Information System (INIS)

    Carlip, S.

    2003-01-01

    Tentative observations and theoretical considerations have recently led to renewed interest in models of fundamental physics in which certain 'constants' vary in time. Assuming fixed black hole mass and the standard form of the Bekenstein-Hawking entropy, Davies, Davis and Lineweaver have argued that the laws of black hole thermodynamics disfavor models in which the fundamental electric charge e changes. I show that with these assumptions, similar considerations severely constrain 'varying speed of light' models, unless we are prepared to abandon cherished assumptions about quantum gravity. Relaxation of these assumptions permits sensible theories of quantum gravity with ''varying constants,'' but also eliminates the thermodynamic constraints, though the black hole mass spectrum may still provide some restrictions on the range of allowable models

  20. A Facile Approach to Prepare Black TiO2 with Oxygen Vacancy for Enhancing Photocatalytic Activity

    Science.gov (United States)

    Chen, Shihao; Xiao, Yang; Hu, Zhengfa; Zhao, Hui; Xie, Wei

    2018-01-01

    Black TiO2 has triggered worldwide research interest due to its excellent photocatalytic properties. However, the understanding of its structure–property relationships and a more effective, facile and versatile method to produce it remain great challenges. We have developed a facile approach to synthesize black TiO2 nanoparticles with significantly improved light absorption in the visible and infrared regions. The experimental results show that oxygen vacancies are the major factors responsible for black coloration. More importantly, our black TiO2 nanoparticles have no Ti3+ ions. These oxygen vacancies could introduce localized states in the bandgap and act as trap centers, significantly decreasing the electron–hole recombination. The photocatalytic decomposition of both rhodamine B and methylene blue demonstrated that, under ultraviolet light irradiation, better photocatalytic performance is achieved with our black TiO2 nanoparticles than with commercial TiO2 nanoparticles. PMID:29659500

  1. Preparation and Integration of ALHAT Precision Landing Technology for Morpheus Flight Testing

    Science.gov (United States)

    Carson, John M., III; Robertson, Edward A.; Pierrottet, Diego F.; Roback, Vincent E.; Trawny, Nikolas; Devolites, Jennifer L.; Hart, Jeremy J.; Estes, Jay N.; Gaddis, Gregory S.

    2014-01-01

    The Autonomous precision Landing and Hazard Avoidance Technology (ALHAT) project has developed a suite of prototype sensors for enabling autonomous and safe precision land- ing of robotic or crewed vehicles on solid solar bodies under varying terrain lighting condi- tions. The sensors include a Lidar-based Hazard Detection System (HDS), a multipurpose Navigation Doppler Lidar (NDL), and a long-range Laser Altimeter (LAlt). Preparation for terrestrial ight testing of ALHAT onboard the Morpheus free- ying, rocket-propelled ight test vehicle has been in progress since 2012, with ight tests over a lunar-like ter- rain eld occurring in Spring 2014. Signi cant work e orts within both the ALHAT and Morpheus projects has been required in the preparation of the sensors, vehicle, and test facilities for interfacing, integrating and verifying overall system performance to ensure readiness for ight testing. The ALHAT sensors have undergone numerous stand-alone sensor tests, simulations, and calibrations, along with integrated-system tests in special- ized gantries, trucks, helicopters and xed-wing aircraft. A lunar-like terrain environment was constructed for ALHAT system testing during Morpheus ights, and vibration and thermal testing of the ALHAT sensors was performed based on Morpheus ights prior to ALHAT integration. High- delity simulations were implemented to gain insight into integrated ALHAT sensors and Morpheus GN&C system performance, and command and telemetry interfacing and functional testing was conducted once the ALHAT sensors and electronics were integrated onto Morpheus. This paper captures some of the details and lessons learned in the planning, preparation and integration of the individual ALHAT sen- sors, the vehicle, and the test environment that led up to the joint ight tests.

  2. To Test or Not to Test: Barriers and Solutions to Testing African American College Students for HIV at a Historically Black College/University.

    Science.gov (United States)

    Hall, Naomi M; Peterson, Jennifer; Johnson, Malynnda

    2014-01-01

    Young African Americans are disproportionately affected by sexually transmitted infections, including HIV. The purpose was to identify reasons that African American college students at a historically Black college/university (HBCU) identified as barriers to HIV testing, and how these barriers can be removed. Fifty-seven heterosexual-identified undergraduate students (ages 18-25) attending an HBCU in the southeastern US participated in a mixed method study. Latent content analytic techniques were used to code the transcripts for themes and categories, and representative quotations were used in the findings. Quantitative data indicates high levels of perceived knowledge about HIV transmission, low perception of risk and concern of contracting HIV, yet continued sexual risk behavior. Qualitative data indicates three main themes used to avoid testing and three themes to encourage testing. Students were forthcoming in discussing the themes around avoidance of HIV testing (being scared to know, preferring not to know, and lack of discussion about HIV) and encouraging testing (group testing, increasing basic knowledge, and showing the reality of HIV). It is important for college healthcare professionals, researchers, and officials to identify appropriate ways to encourage HIV testing, and promote testing as part of overall health.

  3. Directing students to profound open-book test preparation : The relationship between deep learning and open-book test time

    NARCIS (Netherlands)

    Heijne-Penninga, M.; Kuks, J.B.; Hofman, W.H.; Cohen-Schotanus, J.

    2011-01-01

    Background: Considering the growing amount of medical knowledge and the focus of medical education on acquiring competences, using open-book tests seems inevitable. A possible disadvantage of these tests is that students underestimate test preparation. Aims: We examined whether students who used a

  4. From Their Voices: Barriers to HIV Testing among Black Men Who Have Sex with Men Remain

    Directory of Open Access Journals (Sweden)

    Thomas Alex Washington

    2015-10-01

    Full Text Available Background: HIV testing continues to be a major priority for addressing the epidemic among young Black men who have sex with men (BMSM. Methods: This study explored barriers to HIV testing uptake, and recommendations for motivating HIV testing uptake among Black men who have sex with men (BMSM aged 18 to 30. BMSM (N = 36 were recruited through flyers and social media for six focus groups. Results: From the perspectives and experiences of young BMSM, participants recommended that information be included in HIV testing messages that would help young BMSM do self HIV-risk appraisals. Particularly, participants recommended that more knowledge about Pre-Exposure Prophylaxis (PrEP and the role of PrEP in safer-sex practices be provided. This information is important to help those untested, or who infrequently test, better understand their risk and need for testing. Likewise, participants recommended that more information about a person being undetectable and the risk of condomless sex with an HIV negative sex partner; this information will be helpful for both the HIV negative and HIV positive sex partner for making safer sex decisions. Participants also recommended that interventions should focus on more than drug use as risk; the risk posed by the use of alcohol before and during sex deserves attention among young BMSM. Conclusions: These findings may inform new HIV testing interventions being tailored for young BMSM. The interventions should also consider revisiting street-based peer-outreach approaches for those young BMSM with limited access to social media campaigns due to limited access or infrequent use of social media.

  5. Electrically conductive, black thermal control coatings for spacecraft applications. III - Plasma-deposited ceramic matrix

    Science.gov (United States)

    Hribar, V. F.; Bauer, J. L.; O'Donnell, T. P.

    1987-01-01

    Five black, electrically-conductive thermal control coatings have been formulated and tested for application on the Galileo spacecraft. The coatings consist of both organic and inorganic systems applied on titanium, aluminum, and glass/epoxy composite surfaces. The coatings were tested under simulated space environment conditions. Coated specimens were subjected to thermal radiation, convective and combustive heating, and cryogenic conditions over a temperature range between -196 C and 538 C. Mechanical, physical, thermal, electrical, and thermooptical properties are presented for one of these coatings. This paper describes the preparation, characteristics, and spraying of iron titanate on titanium and aluminum, and presents performance results.

  6. Beyond the singularity of the 2-D charged black hole

    International Nuclear Information System (INIS)

    Giveon, Amit; Rabinovici, Eliezer; Sever, Amit

    2003-01-01

    Two dimensional charged black holes in string theory can be obtained as exact SL(2,R) x U(1)/U(1) quotient CFTs. The geometry of the quotient is induced from that of the group, and in particular includes regions beyond the black hole singularities. Moreover, wavefunctions in such black holes are obtained from gauge invariant vertex operators in the SL(2,R) CFT, hence their behavior beyond the singularity is determined. When the black hole is charged we find that the wavefunctions are smooth at the singularities. Unlike the uncharged case, scattering waves prepared beyond the singularity are not fully reflected; part of the wave is transmitted through the singularity. Hence, the physics outside the horizon of a charged black hole is sensitive to conditions set behind the past singularity. (author)

  7. Development of Candidate Reference Materials of Endosulfan Sulfate and Bifenthrin in Black Tea

    Directory of Open Access Journals (Sweden)

    Nurhani Aryana

    2016-03-01

    Full Text Available The candidate reference materials of endosulfan sulfate and bifenthrin in black tea have been developed according to the requirements of ISO Guide 34 and 35. Preparation of candidate material includes grinding and sieving of the black tea leaves, spiking the black tea powder by both analytes, homogenization, and bottling. Homogeneity and short-term stability test were performed using a GC-µECD instrument. Meanwhile, the characterization was carried out by a collaborative study using both of GC-µECD and GC-MS instruments. The uncertainty budget was evaluated from sample inhomogeneity, short-term instability and variability in the characterization procedure. In a dry mass fraction, endosulfan sulfate was assigned to be 491 µg kg-1 with a relative expanded uncertainty of ± 33.2%, and bifenthrin was assigned to be 937 µg kg-1 with a relative expanded uncertainty of ± 18.5%. The candidate reference materials are aimed to support the need of matrix CRM especially for the measurement of pesticide residue for quality assurance work done by laboratories in Indonesia.

  8. 40 CFR 86.152-98 - Vehicle preparation; refueling test.

    Science.gov (United States)

    2010-07-01

    ... 40 Protection of Environment 18 2010-07-01 2010-07-01 false Vehicle preparation; refueling test... PROGRAMS (CONTINUED) CONTROL OF EMISSIONS FROM NEW AND IN-USE HIGHWAY VEHICLES AND ENGINES Emission Regulations for 1977 and Later Model Year New Light-Duty Vehicles and New Light-Duty Trucks and New Otto-Cycle...

  9. Pathfinders on Black Dance in America.

    Science.gov (United States)

    Roy, Loriene, Ed.

    This is a compilation of 18 pathfinders (i.e., a bibliographic instruction aid) on black dance in America, prepared by graduate students in the "Information Resources in the Humanities" and the "Information Resources in the Social Sciences" classes in the Graduate School of Library and Information Science at the University of…

  10. A preparation method and effects of Al-Cr coating on NdFeB sintered magnets

    Energy Technology Data Exchange (ETDEWEB)

    Zheng, Jingwu [College of Chemical Engineering and Materials Science, Zhejiang University of Technology, Hangzhou 310032 (China); Lin, Min, E-mail: linm@nimte.ac.cn [Key Laboratory of Magnetic Materials and Devices, Ningbo Institute of Material Technology and Engineering Chinese Academy of Science, 519 Road Zhuangshi, District Zhenghai, Ningbo 315201, People' s Republic of China (China); Xia, Qingping [College of Chemical Engineering and Materials Science, Zhejiang University of Technology, Hangzhou 310032 (China)

    2012-11-15

    A 50 {mu}m Al-Cr coating on NdFeB sintered magnets was prepared through dipping in solution, shaking dry and heating at 300 Degree-Sign C. The morphology and composition of the Al-Cr coating were investigated with scanning electron microscope, energy dispersive spectrometer and X-ray diffraction. The corrosion resistance of NdFeB sintered magnets with and without the Al-Cr coating was analyzed by normal salt spray, polarization curves and electrochemical impedance spectroscopy. The magnetic properties were measured with a hysteresis loop tracer. The results show that the Al-Cr coating forms an overlapping structure and Al flakes lie nearly parallel to the substrate, which improves the anticorrosion and increases normal salt spray test from 10 to 100 h. The corrosion potential of NdFeB sintered magnets with and without the Al-Cr coating moves positively from -0.67 to -0.48 V, which is in accordance with Nyquist and Bode plots. The Al-Cr coating has little influence on the magnetic properties of the NdFeB sintered magnets. - Highlights: Black-Right-Pointing-Pointer The Al-Cr coating can be prepared by dipping in solution, shaking dry and heating. Black-Right-Pointing-Pointer The coating morphology shows to be an intense overlapping structure. Black-Right-Pointing-Pointer The barrier effect combines with passivation and cathodic protection. Black-Right-Pointing-Pointer The anticorrosion abilities improve while magnetic properties change little. Black-Right-Pointing-Pointer Compared with other surface treatments, this method is convenient and low cost.

  11. Remediation of azo dyes by using household used black tea as an ...

    African Journals Online (AJOL)

    In the present study used black tea and its impregnates were used as an adsorbents for the removal of textile dyes such as methylene blue and malachite green. The impregnation technique was adopted for the preparation of metal impregnates. The present study shows that used black tea and its impregnate exhibit ...

  12. Black holes escaping from domain walls

    International Nuclear Information System (INIS)

    Flachi, Antonino; Sasaki, Misao; Pujolas, Oriol; Tanaka, Takahiro

    2006-01-01

    Previous studies concerning the interaction of branes and black holes suggested that a small black hole intersecting a brane may escape via a mechanism of reconnection. Here we consider this problem by studying the interaction of a small black hole and a domain wall composed of a scalar field and simulate the evolution of this system when the black hole acquires an initial recoil velocity. We test and confirm previous results, however, unlike the cases previously studied, in the more general set-up considered here, we are able to follow the evolution of the system also during the separation, and completely illustrate how the escape of the black hole takes place

  13. Thermal properties of carbon black aqueous nanofluids for solar absorption

    Directory of Open Access Journals (Sweden)

    Han Dongxiao

    2011-01-01

    Full Text Available Abstract In this article, carbon black nanofluids were prepared by dispersing the pretreated carbon black powder into distilled water. The size and morphology of the nanoparticles were explored. The photothermal properties, optical properties, rheological behaviors, and thermal conductivities of the nanofluids were also investigated. The results showed that the nanofluids of high-volume fraction had better photothermal properties. Both carbon black powder and nanofluids had good absorption in the whole wavelength ranging from 200 to 2,500 nm. The nanofluids exhibited a shear thinning behavior. The shear viscosity increased with the increasing volume fraction and decreased with the increasing temperature at the same shear rate. The thermal conductivity of carbon black nanofluids increased with the increase of volume fraction and temperature. Carbon black nanofluids had good absorption ability of solar energy and can effectively enhance the solar absorption efficiency.

  14. The Relationship between Test Preparation and State Test Performance: Evidence from the Measure of Effective Teaching (MET) Project

    Science.gov (United States)

    Li, Hongli; Xiong, Yao

    2018-01-01

    The passage of the NCLB Act enhanced accountability policies in the United States, and standardized testing became prevalent as a policy tool to ensure accountability in K-12 education. Given the high stakes of state administered accountability tests, more school teachers have adopted test-preparation strategies to ensure satisfactory student…

  15. Effect of carbon black composition with sludge palm oil on the curing characteristic and mechanical properties of natural rubber/styrene butadiene rubber compound

    Science.gov (United States)

    Mohamed, R.; Nurazzi, N. Mohd; Huzaifah, M.

    2017-07-01

    This study was conducted to investigate the possibility of utilizing sludge palm oil (SPO) as processing oil, with various amount of carbon black as its reinforcing filler, and its effects on the curing characteristics and mechanical properties of natural rubber/styrene butadiene rubber (NR/SBR) compound. Rubber compound with fixed 15 pphr of SPO loading, and different carbon black loading from 20 to 50 pphr, was prepared using two roll mills. The cure characteristics and mechanical tests that have been conducted are the scorch and cure time analysis, tensile strength and tear strength. Scorch time (ts5) and cure time (t90) of the compound increases with the increasing carbon black loading. The mechanical properties of NR/SBR compound viz. the tensile strength, modulus at 300% strain and tear strength were also improved by the increasing carbon black loading.

  16. Tidal interactions with Kerr black holes

    International Nuclear Information System (INIS)

    Hiscock, W.A.

    1977-01-01

    The tidal deformation of an extended test body falling with zero angular momentum into a Kerr black hole is calculated. Numerical results for infall along the symmetry axis and in the equatorial plane of the black hole are presented for a range of values of a, the specific angular momentum of the black hole. Estimates of the tidal contribution to the gravitational radiation are also given. The tidal contribution in equatorial infall into a maximally rotating Kerr black hole may be of the same order as the center-of-mass contribution to the gravitational radiation

  17. Noncommutative Black Holes at the LHC

    Science.gov (United States)

    Villhauer, Elena Michelle

    2017-12-01

    Based on the latest public results, 13 TeV data from the Large Hadron Collider at CERN has not indicated any evidence of hitherto tested models of quantum black holes, semiclassical black holes, or string balls. Such models have predicted signatures of particles with high transverse momenta. Noncommutative black holes remain an untested model of TeV-scale gravity that offers the starkly different signature of particles with relatively low transverse momenta. Considerations for a search for charged noncommutative black holes using the ATLAS detector will be discussed.

  18. Development of the high-level waste high-temperature melter feed preparation flowsheet for vitrification process testing

    International Nuclear Information System (INIS)

    Seymour, R.G.

    1995-01-01

    High-level waste (HLW) feed preparation flowsheet development was initiated in fiscal year (FY) 1994 to evaluate alternative flowsheets for preparing melter feed for high-temperature melter (HTM) vitrification testing. Three flowsheets were proposed that might lead to increased processing capacity relative to the Hanford Waste Vitrification Plant (HWVP) and that were flexible enough to use with other HLW melter technologies. This document describes the decision path that led to the selection of flowsheets to be tested in the FY 1994 small-scale HTM tests. Feed preparation flowsheet development for the HLW HTM was based on the feed preparation flowsheet that was developed for the HWVP. This approach allowed the HLW program to build upon the extensive feed preparation flowsheet database developed under the HWVP Project. Primary adjustments to the HWVP flowsheet were to the acid adjustment and glass component additions. Developmental background regarding the individual features of the HLW feed preparation flowsheets is provided. Applicability of the HWVP flowsheet features to the new HLW vitrification mission is discussed. The proposed flowsheets were tested at the laboratory-scale at Pacific Northwest Laboratory. Based on the results of this testing and previously established criteria, a reductant-based flowsheet using glycolic acid and a nitric acid-based flowsheet were selected for the FY 1994 small-scale HTM testing

  19. Preparation and properties of homogeneous-reinforced polyvinylidene fluoride hollow fiber membrane

    Energy Technology Data Exchange (ETDEWEB)

    Zhang Xuliang [State Key Laboratory of Hollow Fiber Membrane Materials and Processes, Tianjin Polytechnic University, Tianjin 300387 (China); Xiao Changfa, E-mail: xiaotjpu@163.com [State Key Laboratory of Hollow Fiber Membrane Materials and Processes, Tianjin Polytechnic University, Tianjin 300387 (China); Hu Xiaoyu; Bai Qianqian [State Key Laboratory of Hollow Fiber Membrane Materials and Processes, Tianjin Polytechnic University, Tianjin 300387 (China)

    2013-01-01

    Highlights: Black-Right-Pointing-Pointer The homogeneous-reinforced method has been adopted firstly in preparing of PVDF membranes. Black-Right-Pointing-Pointer The HR membranes have a favorable interfacial bonding between the coating layer and the matrix membrane. Black-Right-Pointing-Pointer The better performance of the HR membranes in protein solution can indirectly improve the service life of membranes. - Abstract: Homogeneous-reinforced (HR) polyvinylidene fluoride (PVDF) hollow fiber membranes include PVDF polymer solutions (coating layer) and the matrix membrane prepared through the dry-wet spinning process. The performance of HR membranes varies with the polymer concentration in the polymer solutions and is characterized in terms of pure water flux, rejection of protein, porosity, infiltration property, a mechanical strength test, and morphology observations by a field emission scanning electron microscope (FESEM). The results of this study indicate that the tensile strength of the HR PVDF membranes decreases slights compared with that of the matrix membrane, but the elongation at break increases much more and the hollow fiber membranes are endowed with better flexibility performance. The HR PVDF hollow fiber membranes have a favorable interfacial bonding between the coating layer and the matrix membrane, as shown by FESEM. The infiltration property is characterized by the contact angle experiments. Pure water flux decreases while the rejection ratio with an increase in polymer concentration increasing. The protein solution flux of the HR PVDF membranes is higher than that of the matrix membrane after 100 min of infiltration.

  20. Black coal in Australia 1985-86

    Energy Technology Data Exchange (ETDEWEB)

    1986-01-01

    The annual publication contains comprehensive statistical details of the Australian black coal industry. Included are statistics on coal supply and disposal, production plant and equipment, coal preparation, capital expenditure, employees, exports, coal consumption, resources. Maps of mine locations are included, also tables showing coal supply and disposal, production figures, plant and equipment, employees, exports, resources.

  1. Hydroxyisohexyl 3-cyclohexene carboxaldehyde (lyral) in patch test preparations under varied storage conditions.

    Science.gov (United States)

    Hamann, Dathan; Hamann, Carsten R; Zimerson, Erik; Bruze, Magnus

    2013-01-01

    The common practice of preparing patch tests in advance has recently been called into question by researchers. It has been established that fragrance compounds are volatile and their testing efficacy may be affected by storage conditions and preparation. Allergens in fragrance mix I rapidly decrease in concentration after preapplication to test chambers. This study aimed to investigate the volatility of hydroxyisohexyl 3-cyclohexene carboxaldehyde (HICC) in petrolatum when stored in test chambers and to explore the correlation between vapor pressure and allergen loss in petrolatum during preparation and storage. Standardized HICC in petrolatum was prepared and stored in IQ Chambers and Finn Chambers with covers at 5°C, 25°C, and 35°C, and concentration was analyzed at intervals for up to 9 days using gel permeation chromatography. Changes in HICC concentrations were not statistically significant at 8 hours at 5°C, 25°C, and 35°C. After 9 days, HICC concentrations were found to fall approximately 30% when stored at 35°C, 10% at 25°C, and less than 5% at 5°C. There was no significant difference between IQ and Finn chambers. Hydroxyisohexyl 3-cyclohexene carboxaldehyde concentrations are more stable in petrolatum than many other studied fragrance allergens, but HICC is still at risk for decreasing concentration when exposed to ambient air or heat for prolonged periods.

  2. Preparations for deuterium tritium experiments on the Tokamak Fusion Test Reactor

    International Nuclear Information System (INIS)

    Hawryluk, R.J.; Adler, H.; Alling, P.; Ancher, C.; Anderson, H.; Anderson, J.W.; Arunasalam, V.; Ascione, G.; Ashcroft, D.; Barnes, G.

    1994-04-01

    The final hardware modifications for tritium operation have been completed for the Tokamak Fusion Test Reactor (TFTR). These activities include preparation of the tritium gas handling system, installation of additional neutron shielding, conversion of the toroidal field coil cooling system from water to a Fluorinet trademark system, modification of the vacuum system to handle tritium, preparation and testing of the neutral beam system for tritium operation and a final deuterium-deuterium (D-D) run to simulate expected deuterium-tritium (D-T) operation. Testing of the tritium system with low concentration tritium has successfully begun. Simulation of trace and high power D-T experiments using D-D have been performed. The physics objectives of D-T operation are production of ∼ 10 megawatts (MW) of fusion power, evaluation of confinement and heating in deuterium-tritium plasmas, evaluation of α-particle heating of electrons, and collective effects driven by alpha particles and testing of diagnostics for confined α-particles. Experimental results and theoretical modeling in support of the D-T experiments are reviewed

  3. Preparations for deuterium--tritium experiments on the Tokamak Fusion Test Reactor*

    International Nuclear Information System (INIS)

    Hawryluk, R.J.; Adler, H.; Alling, P.; Ancher, C.; Anderson, H.; Anderson, J.L.; Anderson, J.W.; Arunasalam, V.; Ascione, G.; Aschroft, D.; Barnes, C.W.; Barnes, G.; Batchelor, D.B.; Bateman, G.; Batha, S.; Baylor, L.A.; Beer, M.; Bell, M.G.; Biglow, T.S.; Bitter, M.; Blanchard, W.; Bonoli, P.; Bretz, N.L.; Brunkhorst, C.; Budny, R.; Burgess, T.; Bush, H.; Bush, C.E.; Camp, R.; Caorlin, M.; Carnevale, H.; Chang, Z.; Chen, L.; Cheng, C.Z.; Chrzanowski, J.; Collazo, I.; Collins, J.; Coward, G.; Cowley, S.; Cropper, M.; Darrow, D.S.; Daugert, R.; DeLooper, J.; Duong, H.; Dudek, L.; Durst, R.; Efthimion, P.C.; Ernst, D.; Faunce, J.; Fonck, R.J.; Fredd, E.; Fredrickson, E.; Fromm, N.; Fu, G.Y.; Furth, H.P.; Garzotto, V.; Gentile, C.; Gettelfinger, G.; Gilbert, J.; Gioia, J.; Goldfinger, R.C.; Golian, T.; Gorelenkov, N.; Gouge, M.J.; Grek, B.; Grisham, L.R.; Hammett, G.; Hanson, G.R.; Heidbrink, W.; Hermann, H.W.; Hill, K.W.; Hirshman, S.; Hoffman, D.J.; Hosea, J.; Hulse, R.A.; Hsuan, H.; Jaeger, E.F.; Janos, A.; Jassby, D.L.; Jobes, F.C.; Johnson, D.W.; Johnson, L.C.; Kamperschroer, J.; Kesner, J.; Kugel, H.; Kwon, S.; Labik, G.; Lam, N.T.; LaMarche, P.H.; Laughlin, M.J.; Lawson, E.; LeBlanc, B.; Leonard, M.; Levine, J.; Levinton, F.M.; Loesser, D.; Long, D.; Machuzak, J.; Mansfield, D.E.; Marchlik, M.; Marmar, E.S.; Marsala, R.; Martin, A.; Martin, G.; Mastrocola, V.; Mazzucato, E.; McCarthy, M.P.; Majeski, R.; Mauel, M.; McCormack, B.; McCune, D.C.; McGuire, K.M.; Meade, D.M.; Medley, S.S.; Mikkelsen, D.R.; Milora, S.L.; Monticello, D.; Mueller, D.; Murakami, M.; Murphy, J.A.; Nagy, A.; Navratil, G.A.; Nazikian, R.; Newman, R.; Nishitani, T.; Norris, M.; O'Connor, T.; Oldaker, M.; Ongena, J.; Osakabe, M.; Owens, D.K.; Park, H.; Park, W.; Paul, S.F.; Pavlov, Y.I.; Pearson, G.; Perkins, F.; Perry, E.; Persing, R.; Petrov, M.; Phillips, C.K.; Pitcher, S.; Popovichev, S.; Qualls, A.L.; Raftopoulos, S.; Ramakrishnan, R.; Ramsey, A.; Rasmussen, D.A.; Redi, M.H.

    1994-01-01

    The final hardware modifications for tritium operation have been completed for the Tokamak Fusion Test Reactor (TFTR) [Fusion Technol. 21, 1324 (1992)]. These activities include preparation of the tritium gas handling system, installation of additional neutron shielding, conversion of the toroidal field coil cooling system from water to a Fluorinert TM system, modification of the vacuum system to handle tritium, preparation, and testing of the neutral beam system for tritium operation and a final deuterium--deuterium (D--D) run to simulate expected deuterium--tritium (D--T) operation. Testing of the tritium system with low concentration tritium has successfully begun. Simulation of trace and high power D--T experiments using D--D have been performed. The physics objectives of D--T operation are production of ∼10 MW of fusion power, evaluation of confinement, and heating in deuterium--tritium plasmas, evaluation of α-particle heating of electrons, and collective effects driven by alpha particles and testing of diagnostics for confined α particles. Experimental results and theoretical modeling in support of the D--T experiments are reviewed

  4. Electrochemical properties of Super P carbon black as an anode active material for lithium-ion batteries

    International Nuclear Information System (INIS)

    Gnanamuthu, RM.; Lee, Chang Woo

    2011-01-01

    Highlights: → A novel attempt of Super P carbon black as an anode active material for lithium-ion batteries. → The first discharge capacity was approximately 1256 mAh g -1 and at the end of 20th cycling the capacity was 610 mAh g -1 at 0.1 C rate. → Coulombic efficiency of Super P carbon black electrode was maintained about 84% at the end of cycling. - Abstract: A new approach to investigate upon the electrochemical properties of Super P carbon black anode material is attempted and compared with conventional mesophase pitch-based carbon fibers (MPCFs) anode material for lithium-ion batteries. The prepared Super P carbon black electrodes are characterized using transmission electron microscope (TEM). The assembled 2032-type coin cells are electrochemically characterized by ac impedance spectroscopic and cyclic voltammetric methods. The electrochemical performance of charge and discharge was analyzed using a battery cycler at 0.1 C rate and cut-off potentials of 1.20 and 0.01 V vs. Li/Li + . The electrochemical test illustrates that the discharge capacity corresponding to Li intercalation into the Super P carbon black electrode is higher and coulombic efficiency is maintained approximately 84% at the end of the 20th cycling at room temperature.

  5. Application of ultrasonic extraction method in the preparation of the directive action beverage from black currant

    Directory of Open Access Journals (Sweden)

    N. S. Rodionova

    2016-01-01

    Full Text Available The article presents the results of experimental determination of physical-and chemical parameters, the amount of anthocyanins, the definition of color and organoleptic characteristics of the beverage prepared with ultrasonic extraction method in comparison with the fruit-drink, obtained according to traditional recipe. Black currant was chosen the main raw material for the development of the beverage production technology. It is characterized by a high content of bioactive components that increase the adaptive abilities of human body. The purpose is to use ultrasonic extraction method in the preparation of functionally directed actions beverages. Extractor with submerged ultrasonic emitter was used as an experimental device. The essence of its operation is as follows: a mixture of the extractant and the plant substrate in different ratios was loaded into a container with the emitter, then the ultrasonic generator was turned on. The vibrations of ultrasonic frequency (22 kHz made high-frequency mechanical vibrations that caused the formation of intense cavitation areas and diffuse dissolution of cell substrates in the extractant in the treated mixture. The ultrasonic extraction technique involves brief contact of berries and extractant (up to 15 minutes upon application of ultrasonic vibrations. With an increase in exposure time, the yield of biologically active substances increases to reach an equilibrium state corresponding to the most complete exhaustion of raw materials. All this leads to a significant acceleration of the transition from the active ingredients from the raw materials into the extractant to obtain a product with improved physical - and chemical, organoleptic characteristics, as well as a higher antioxidant activity.

  6. Looking for the invisible universe - Black matter, black energy, black holes

    International Nuclear Information System (INIS)

    Elbaz, David

    2016-01-01

    As the discovery of the expansion of the universe and of black holes put the study of cosmology into question again because it now refers to invisible things such as black holes, black energy and black matter, the author proposes an other view on the universe within such a context. He first discusses these three enigmas of black matter, black energy and black holes. In a second part, he addresses, discusses and comments five illusions: the Uranian illusion (questions of the existence of an anti-world, of black matter temperature), the Mercurian illusion (quantum gravity, the string theory), the Martian illusion (a patchwork universe, the illusion of the infinite), the cosmic Maya (the John Wheeler's cup, the holographic universe), and the narcissistic illusion

  7. Studies on black anodic coatings for spacecraft thermal control applications

    Energy Technology Data Exchange (ETDEWEB)

    Uma Rani, R.; Subba Rao, Y.; Sharma, A.K. [ISRO Satellite Centre, Bangalore (India). Thermal Systems Group

    2011-10-15

    An inorganic black colouring process using nickel sulphate and sodium sulphide was investigated on anodized aluminium alloy 6061 to provide a flat absorber black coating for spacecraft thermal control applications. Influence of colouring process parameters (concentration, pH) on the physico-optical properties of black anodic film was investigated. The nature of black anodic film was evaluated by the measurement of film thickness, micro hardness and scanning electron microscopy (SEM). Energy dispersive X-ray spectroscopy studies confirmed the presence of nickel and sulphur in the black anodic coating. Electrochemical impedance spectroscopy (EIS) was used to evaluate the corrosion resistance of the coating. The environmental tests, namely, humidity, corrosion resistance, thermal cycling and thermo vacuum performance tests were used to evaluate the space worthiness of the coating. Optical properties of the film were measured before and after each environmental test to ascertain its stability in harsh space environment. The black anodic films provide higher thermal emittance ({proportional_to} 0.90) and solar absorptance ({proportional_to} 0.96) and their high stability during the environmental tests indicated their suitability for space and allied applications. (orig.)

  8. Gravitational polarizability of black holes

    International Nuclear Information System (INIS)

    Damour, Thibault; Lecian, Orchidea Maria

    2009-01-01

    The gravitational polarizability properties of black holes are compared and contrasted with their electromagnetic polarizability properties. The 'shape' or 'height' multipolar Love numbers h l of a black hole are defined and computed. They are then compared to their electromagnetic analogs h l EM . The Love numbers h l give the height of the lth multipolar 'tidal bulge' raised on the horizon of a black hole by faraway masses. We also discuss the shape of the tidal bulge raised by a test-mass m, in the limit where m gets very close to the horizon.

  9. 'Triply cursed': racism, homophobia and HIV-related stigma are barriers to regular HIV testing, treatment adherence and disclosure among young Black gay men.

    Science.gov (United States)

    Arnold, Emily A; Rebchook, Gregory M; Kegeles, Susan M

    2014-06-01

    In the USA, young Black gay men are disproportionately impacted upon by HIV. In this qualitative study consisting of in-depth interviews with 31 young Black gay men and nine service providers, where we used thematic analysis to guide our interpretations, we found that HIV-related stigma and homophobia, within the larger societal context of racism, were related to sexual risk behaviour, reluctance to obtain HIV testing or care, lower adherence to treatment medication, and non-disclosure of a positive HIV status to sexual partners. Participants experienced homophobia and HIV-related stigma from churches and families within the Black community and from friends within the Black gay community, which otherwise provide support in the face of racism. Vulnerability to HIV was related to strategies that young Black gay men enacted to avoid being stigmatised or as a way of coping with alienation and rejection.

  10. Testing Dust Control Preparation with Respect to Mine Employee Exposure to Inhalling Chemical Agents

    Directory of Open Access Journals (Sweden)

    Eugeniusz Orszulik

    2013-01-01

    Full Text Available This paper presents the results of tests used in dust hazard prevention for air-water spraying devices in collieries. The purpose of the tests was to evaluate mine employees’ exposure to inhalling chemical agents when the ZWILKOP ZW-10 preparation is used. The paper presents the results of the measurements of concentration, in a mine atmosphere, of the following chemical agents: hazardous substances 2-(2-butoxyethoxyethanol and 2-ethylhexan-1-ol, constituting ingredients of the preparation at mine employees’ workstations. The tests were performed during work related to the mining of coal in inclined drift C31, seam 415/1-2 on the premises of “Borynia-Zofiówka-Jastrzębie” Hard Coal Mine, Jastrzębie-Zdrój, Poland, using the TELESTO mist systems. Using aqueous solutions for the preparation at concentrations of 15 and 20‰ causes no exceedance of the allowable mine air concentrations for the chemical agents tested.

  11. Low-scale gravity black holes at LHC

    CERN Document Server

    Regos, E; Gamsizkan, H; Trocsanyi, Z

    2009-01-01

    We search for extra dimensions by looking for black holes at LHC. Theoretical investigations provide the basis for the collider experiments. We use black hole generators to simulate the experimental signatures (colour, charge, spectrum of emitted particles, missing transverse energy) of black holes at LHC in models with TeV scale quantum gravity, rotation, fermion splitting, brane tension and Hawking radiation. We implement the extra-dimensional simulations at the CMS data analysis and test further beyond standard models of black holes too.

  12. Merging Black Holes

    Science.gov (United States)

    Centrella, Joan

    2012-01-01

    The final merger of two black holes is expected to be the strongest source of gravitational waves for both ground-based detectors such as LIGO and VIRGO, as well as future. space-based detectors. Since the merger takes place in the regime of strong dynamical gravity, computing the resulting gravitational waveforms requires solving the full Einstein equations of general relativity on a computer. For many years, numerical codes designed to simulate black hole mergers were plagued by a host of instabilities. However, recent breakthroughs have conquered these instabilities and opened up this field dramatically. This talk will focus on.the resulting 'gold rush' of new results that is revealing the dynamics and waveforms of binary black hole mergers, and their applications in gravitational wave detection, testing general relativity, and astrophysics

  13. Prepare Your Child For Reading Tests: Tips for Parents = Prepare a sus hijos para tomar pruebas de lectura: Ideas para padres.

    Science.gov (United States)

    Bachman, Tori Mello

    Parents can help their children prepare for reading tests in a number of ways, not only just before the test, but also with everyday activities. There are generally two types of reading tests given to students: tests given by teachers throughout the year to see what information students have retained, and more formal, often standardized, tests…

  14. Timelike geodesics around a charged spherically symmetric dilaton black hole

    Directory of Open Access Journals (Sweden)

    Blaga C.

    2015-01-01

    Full Text Available In this paper we study the timelike geodesics around a spherically symmetric charged dilaton black hole. The trajectories around the black hole are classified using the effective potential of a free test particle. This qualitative approach enables us to determine the type of orbit described by test particle without solving the equations of motion, if the parameters of the black hole and the particle are known. The connections between these parameters and the type of orbit described by the particle are obtained. To visualize the orbits we solve numerically the equation of motion for different values of parameters envolved in our analysis. The effective potential of a free test particle looks different for a non-extremal and an extremal black hole, therefore we have examined separately these two types of black holes.

  15. The Crisis in Black and Black.

    Science.gov (United States)

    Hutchinson, Earl Ofari

    These essays explore why the historic conflict between blacks and whites in the United States has become a crisis that divides many African Americans. The changing racial dynamic is not marked by conflicts. between the black middle class and the poor, black men and women, the black intellectual elite and rappers, black politicians and the urban…

  16. Li_4Ti_5O_1_2/Ketjen Black with open conductive frameworks for high-performance lithium-ion batteries

    International Nuclear Information System (INIS)

    Zhang, Yang; Dong, Hui; Zhang, Huang; Liu, Yijun; Ji, Mandi; Xu, Yunlong; Wang, Qingqing; Luo, Lei

    2016-01-01

    Graphical abstract: The Li_4Ti_5O_1_2/Ketjen Black composites are synthesized via a simple hydrothermal method. As an anode for lithium ion battery, the composite exhibits ultrahigh capacity and excellent low temperature performance. - Highlights: • Mesoporous LTO/KB composites were synthesized via hydrothermal method. • KB is used as carbon template and conductive additive. • The LTO/KB electrode without carbon black was fabricated. • This as-prepared electrode shows excellent rate capacity performance. • LTO/KB composite exhibits ultrahigh cycle performance at low temperature. - Abstract: The Li_4Ti_5O_1_2/Ketjen Black composites are synthesized via a simple hydrothermal method. The materials are characterized by XRD, SEM, HR-TEM, EDS, galvanostatic charge/discharge test, CV and EIS. The results indicate that Li_4Ti_5O_1_2 (LTO) particles grow both in the pores and on the surface of mesoporous Ketjen Black (KB) forming open conductive frameworks and the Ketjen Black works as host forthe growth of Li_4Ti_5O_1_2 primary nanoparticles. The LTO/KB electrode is fabricated without extra carbon black conductive agents and exhibits excellent electrochemical performances, especially at low temperature. The improved performances can be attributed to the presence of mesoporous Ketjen Black conductive templates with high electronic conductivity and formed 3D frameworks beneficial to the lithium ion diffusion.

  17. The Effects of Tutoring in Preparing Chinese Students for the Scholastic Aptitude Test

    Science.gov (United States)

    Chen, Li

    2009-01-01

    Scholastic Aptitude Test, called SAT, has an immense influence in Chinese education. Most Chinese students choose to attend tutoring programs outside of the school curriculum to help them prepare. This study explores the tutoring programs both in China and the United States to assess variables that affect the quality of their preparation.…

  18. Black Self-Esteem and Desegregated Schools.

    Science.gov (United States)

    Drury, Darrel W.

    1980-01-01

    Discusses a study to determine attitudes among Black and White students in 194 southern high schools regarding desegregation. Data are presented on differences between schools; test-score achievement; and variations in self-esteem among students in predominantly White, Black, and racially mixed schools. Findings are interpreted in light of…

  19. Black hole binary OJ287 as a testing platform for general relativity

    International Nuclear Information System (INIS)

    Valtonen, M J; Gopakumar, A; Mikkola, S; Wiik, K; Lehto, H J

    2014-01-01

    The blazar OJ287 is the most promising (and the only) case for an extragalactic binary black hole system inspiralling under the action of gravitational radiation reaction. At present, though it is not possible to directly observe the binary components, it is possible to observe the jet emanating from the primary black hole. We have argued that the orbital motion of the secondary black hole is reflected in the wobble of the jet, and demonstrated that the wobble is orbital position dependent. The erratic wobble of the jet is analyzed by taking into account the binary nature of the system, and we have found that the erratic component of jet wobble is very small

  20. Building a "Lifetime Circle": English Education in the Age of #BlackLivesMatter

    Science.gov (United States)

    Winn, Maisha T.

    2018-01-01

    This article argues that, to prepare teachers in the era of #BlackLivesMatter, there must be a radical reframing of teacher education in which teachers learn to disentangle their teaching from the culture of Mass Incarceration and the criminalization of Black and Brown people in the context of the United States in their practice. Using a…

  1. Characterization of black and white chromium electrodeposition films. Surface and optical properties

    Energy Technology Data Exchange (ETDEWEB)

    Aguilar, M.; Palomar-Pardave, M. [Departamento de Materiales, UAM-Azcapotzalco, Av. San Pablo No. 180, Col. Reynosa Tamaulipas, Mexico D.F. 02200 (Mexico); Barrera, E. [Departamento de Ingenieria de Procesos e Hidraulica, Universidad Autonoma Metropolitana - Iztapalapa, Av. Rafael Atlixco No. 186, Col. Vicentina, Mexico, D.F. 09340 (Mexico); Huerta, L.; Muhl, S. [Instituto de Investigaciones en Materiales, UNAM, Mexico, D.F. 04510 (Mexico)

    2003-11-01

    Thin films of black and white chromium have been prepared by electrodeposition on stainless steel substrates. The potentiodynamic and potentiostatic technique was used in order to prepare these materials. XRD, XPS, SEM and spectral reflectance in the UV-Visible-near IR and medium IR ranges, for both films coatings were characterized. From the SEM analysis, it was found while the black chromium has a lamellar morphology that leads to a strong dispersion level, the white one has a flat morphology. The chemical composition of these thin films was determined by XRD and XPS technique. The XRD results showed that in both cases chromium is the main bulk chemical compound in both films. However, from XPS analysis of these surfaces, it was possible to determine that the most external layers of the films are made of different kinds of chromium compounds. The black chromium film has better optical properties to transform solar energy into thermal energy, and these properties remain practically constant even when heat treated to a high temperature, 400 C. On the other hand the white chromium film is a better substrate for hydrogen evolution reactions than the black one.

  2. 9 CFR 147.8 - Procedures for preparing egg yolk samples for diagnostic tests.

    Science.gov (United States)

    2010-01-01

    ... samples for diagnostic tests. 147.8 Section 147.8 Animals and Animal Products ANIMAL AND PLANT HEALTH... IMPROVEMENT PLAN Blood Testing Procedures § 147.8 Procedures for preparing egg yolk samples for diagnostic... for diagnostic testing. (b) The authorized laboratory must identify each egg as to the breeding flock...

  3. The Little Black Book of Project Management

    CERN Document Server

    Thomsett, Michael C

    2009-01-01

    For nearly twenty years, The Little Black Book of Project Management has provided businesspeople everywhere with a quick and effective introduction to project management tools and methodology. The revised and updated third edition reflects the newest techniques, the latest project management software, as well as the most recent changes to the Project Management Body of Knowledge (PMBOK™). Readers will find invaluable strategies for: • Organizing any project • Choosing the project team • Preparing a budget and sticking to it • Scheduling, flowcharting, and controlling a project • Preparing proj

  4. Particle accelerators inside spinning black holes.

    Science.gov (United States)

    Lake, Kayll

    2010-05-28

    On the basis of the Kerr metric as a model for a spinning black hole accreting test particles from rest at infinity, I show that the center-of-mass energy for a pair of colliding particles is generically divergent at the inner horizon. This shows not only that classical black holes are internally unstable, but also that Planck-scale physics is a characteristic feature within black holes at scales much larger that the Planck length. The novel feature of the divergence discussed here is that the phenomenon is present only for black holes with rotation, and in this sense it is distinct from the well-known Cauchy horizon instability.

  5. Lignin derivatives from desilicated rice straw soda black liquor

    Energy Technology Data Exchange (ETDEWEB)

    El-Taraboulsi, M A; Nasser, M M

    1979-01-01

    Carboxymethyl lignin, cyanoethyl lignin, carboxyethyl lignin, and aminopropyl lignin were prepared from alkali lignin of rice straw black liquor (after disilication by storage for 1 wk to 1 yr) and used as sizes for paper, drilling fluid additives and flocculants.

  6. Gedanken experiments on nearly extremal black holes and the third law

    International Nuclear Information System (INIS)

    Chirco, Goffredo; Liberati, Stefano; Sotiriou, Thomas P.

    2010-01-01

    A gedanken experiment in which a black hole is pushed to spin at its maximal rate by tossing into it a test body is considered. After demonstrating that this is kinematically possible for a test body made of reasonable matter, we focus on its implications for black hole thermodynamics and the apparent violation of the third law (unattainability of the extremal black hole). We argue that this is not an actual violation, due to subtleties in the absorption process of the test body by the black hole, which are not captured by the purely kinematic considerations.

  7. Preparation, characterization and evaluation of electrocatalysts supported on functionalized carbon black for polymer exchange membrane fuel cell applications; Preparacao, caracterizacao e avaliacao de eletrocatalisadores suportados em carbono funcionalizado para aplicacao em celulas a combustivel tipo PEM

    Energy Technology Data Exchange (ETDEWEB)

    Carmo, Marcelo do

    2008-12-18

    The fuel cell technology associated with the growing exigency of low environmental impact energy became prosperous in the world energy scenery. The fuel cell is basically a device that converts directly the chemical energy of a fuel into electrical and thermal energy with a continuous operation by the constant feed of a fuel. Especially, the carbon black Vulcan XC72 is usually employed as an electro catalyst support, and some factors as an accessible and high surface area in order to get maximum particles dispersion, pore size, adequate pore distribution and the presence of functional groups in the carbon black surface are considered fundamental characteristics for an innovative materials development. However, the Vulcan XC72 still reveals insufficient conditions for these purposes. This study consists in the preparation and in the physical chemical characterization of functionalized carbon black by hydrogen peroxide and by polymeric chains with proton conduction properties, and its posterior utilization as electro catalyst support for PEMFC and DMFC application. After the carbon functionalization, an improvement in the carbon black dispersion in water media was observed, a beneficial effect for electro catalyst preparation. It was also observed, that the functional groups and the polymeric chains worked as stabilizers in the particle growing, producing much more homogeneous electrocatalysts, exhibiting smaller average particle size. Especially, in the case of polymeric chains functionalization, a decrease in the ohmic drop was observed for this system, attributed to an improvement in the proton transference. (author)

  8. Lessons learned in preparing method 29 filters for compliance testing audits.

    Science.gov (United States)

    Martz, R F; McCartney, J E; Bursey, J T; Riley, C E

    2000-01-01

    Companies conducting compliance testing are required to analyze audit samples at the time they collect and analyze the stack samples if audit samples are available. Eastern Research Group (ERG) provides technical support to the EPA's Emission Measurements Center's Stationary Source Audit Program (SSAP) for developing, preparing, and distributing performance evaluation samples and audit materials. These audit samples are requested via the regulatory Agency and include spiked audit materials for EPA Method 29-Metals Emissions from Stationary Sources, as well as other methods. To provide appropriate audit materials to federal, state, tribal, and local governments, as well as agencies performing environmental activities and conducting emission compliance tests, ERG has recently performed testing of blank filter materials and preparation of spiked filters for EPA Method 29. For sampling stationary sources using an EPA Method 29 sampling train, the use of filters without organic binders containing less than 1.3 microg/in.2 of each of the metals to be measured is required. Risk Assessment testing imposes even stricter requirements for clean filter background levels. Three vendor sources of quartz fiber filters were evaluated for background contamination to ensure that audit samples would be prepared using filters with the lowest metal background levels. A procedure was developed to test new filters, and a cleaning procedure was evaluated to see if a greater level of cleanliness could be achieved using an acid rinse with new filters. Background levels for filters supplied by different vendors and within lots of filters from the same vendor showed a wide variation, confirmed through contact with several analytical laboratories that frequently perform EPA Method 29 analyses. It has been necessary to repeat more than one compliance test because of suspect metals background contamination levels. An acid cleaning step produced improvement in contamination level, but the

  9. Recycle Waste Collection Tank (RWCT) simulant testing in the PVTD feed preparation system

    International Nuclear Information System (INIS)

    Abrigo, G.P.; Daume, J.T.; Halstead, S.D.; Myers, R.L.; Beckette, M.R.; Freeman, C.J.; Hatchell, B.K.

    1996-03-01

    (This is part of the radwaste vitrification program at Hanford.) RWCT was to routinely receive final canister decontamination sand blast frit and rinse water, Decontamination Waste Treatment Tank bottoms, and melter off-gas Submerged Bed Scrubber filter cake. In order to address the design needs of the RWCT system to meet performance levels, the PNL Vitrification Technology (PVTD) program used the Feed Preparation Test System (FPTS) to evaluate its equipment and performance for a simulant of RWCT slurry. (FPTS is an adaptation of the Defense Waste Processing Facility feed preparation system and represents the initially proposed Hanford Waste Vitrification Plant feed preparation system designed by Fluor-Daniel, Inc.) The following were determined: mixing performance, pump priming, pump performance, simulant flow characterization, evaporator and condenser performance, and ammonia dispersion. The RWCT test had two runs, one with and one without tank baffles

  10. Relativistic hydrodynamic evolutions with black hole excision

    International Nuclear Information System (INIS)

    Duez, Matthew D.; Shapiro, Stuart L.; Yo, H.-J.

    2004-01-01

    We present a numerical code designed to study astrophysical phenomena involving dynamical spacetimes containing black holes in the presence of relativistic hydrodynamic matter. We present evolutions of the collapse of a fluid star from the onset of collapse to the settling of the resulting black hole to a final stationary state. In order to evolve stably after the black hole forms, we excise a region inside the hole before a singularity is encountered. This excision region is introduced after the appearance of an apparent horizon, but while a significant amount of matter remains outside the hole. We test our code by evolving accurately a vacuum Schwarzschild black hole, a relativistic Bondi accretion flow onto a black hole, Oppenheimer-Snyder dust collapse, and the collapse of nonrotating and rotating stars. These systems are tracked reliably for hundreds of M following excision, where M is the mass of the black hole. We perform these tests both in axisymmetry and in full 3+1 dimensions. We then apply our code to study the effect of the stellar spin parameter J/M 2 on the final outcome of gravitational collapse of rapidly rotating n=1 polytropes. We find that a black hole forms only if J/M 2 2 >1, the collapsing star forms a torus which fragments into nonaxisymmetric clumps, capable of generating appreciable 'splash' gravitational radiation

  11. “Triply cursed”: Racism, homophobia, and HIV-related stigma are barriers to regular HIV testing, treatment adherence, and disclosure among young Black gay men

    Science.gov (United States)

    Arnold, Emily A.; Rebchook, Gregory M.; Kegeles, Susan M.

    2014-01-01

    In the USA, young Black gay men are disproportionately impacted by HIV. In this qualitative study consisting of in-depth interviews with 31 young Black gay men and 9 service providers, where we used thematic analysis to guide our interpretations, we found that HIV-related stigma and homophobia, within the larger societal context of racism, were related to sexual risk behaviour, reluctance to obtain HIV testing or care, lower adherence to treatment medication, and disclosure of a positive HIV status to sexual partners. Participants experienced homophobia and HIV-related stigma from churches and families within the Black community, and from friends within the Black gay community, that otherwise provide support in the face of racism. Vulnerability to HIV was related to strategies that young Black gay men enacted to avoid being stigmatised or as a way of coping with their alienation and rejection. PMID:24784224

  12. Standard practice for preparation and use of direct tension stress-corrosion test specimens

    CERN Document Server

    American Society for Testing and Materials. Philadelphia

    1985-01-01

    1.1 This practice covers procedures for designing, preparing, and using ASTM standard tension test specimens for investigating susceptibility to stress-corrosion cracking. Axially loaded specimens may be stressed quantitatively with equipment for application of either a constant load, constant strain, or with a continuously increasing strain. 1.2 Tension test specimens are adaptable for testing a wide variety of product forms as well as parts joined by welding, riveting, or various other methods. 1.3 The exposure of specimens in a corrosive environment is treated only briefly because other standards are being prepared to deal with this aspect. Meanwhile, the investigator is referred to Practices G35, G36, G37, and G44, and to ASTM Special Technical Publication 425 (1).

  13. Fabrication of black-gold coatings by glancing angle deposition with sputtering

    Directory of Open Access Journals (Sweden)

    Alan Vitrey

    2017-02-01

    Full Text Available The fabrication of black-gold coatings using sputtering is reported here. Glancing angle deposition with a rotating substrate is needed to obtain vertical nanostructures. Enhanced light absorption is obtained in the samples prepared in the ballistic regime with high tilt angles. Under these conditions the diameter distribution of the nanostructures is centered at about 60 nm and the standard deviation is large enough to obtain black-metal behavior in the visible range.

  14. White dwarfs - black holes

    International Nuclear Information System (INIS)

    Sexl, R.; Sexl, H.

    1975-01-01

    The physical arguments and problems of relativistic astrophysics are presented in a correct way, but without any higher mathematics. The book is addressed to teachers, experimental physicists, and others with a basic knowledge covering an introductory lecture in physics. The issues dealt with are: fundamentals of general relativity, classical tests of general relativity, curved space-time, stars and planets, pulsars, gravitational collapse and black holes, the search for black holes, gravitational waves, cosmology, cosmogony, and the early universe. (BJ/AK) [de

  15. Six-dimensional localized black holes: Numerical solutions

    International Nuclear Information System (INIS)

    Kudoh, Hideaki

    2004-01-01

    To test the strong-gravity regime in Randall-Sundrum braneworlds, we consider black holes bound to a brane. In a previous paper, we studied numerical solutions of localized black holes whose horizon radii are smaller than the AdS curvature radius. In this paper, we improve the numerical method and discuss properties of the six-dimensional (6D) localized black holes whose horizon radii are larger than the AdS curvature radius. At a horizon temperature T≅1/2πl, the thermodynamics of the localized black hole undergo a transition with its character changing from a 6D Schwarzschild black hole type to a 6D black string type. The specific heat of the localized black holes is negative, and the entropy is greater than or nearly equal to that of the 6D black strings with the same thermodynamic mass. The large localized black holes show flattened horizon geometries, and the intrinsic curvature of the horizon four-geometry becomes negative near the brane. Our results indicate that the recovery mechanism of lower-dimensional Einstein gravity on the brane works even in the presence of the black holes

  16. Black Titanium Dioxide Nanomaterials in Photocatalysis

    Directory of Open Access Journals (Sweden)

    Xiaodong Yan

    2017-01-01

    Full Text Available Titanium dioxide (TiO2 nanomaterials are widely considered to be state-of-the-art photocatalysts for environmental protection and energy conversion. However, the low photocatalytic efficiency caused by large bandgap and rapid recombination of photo-excited electrons and holes is a challenging issue that needs to be settled for their practical applications. Structure engineering has been demonstrated to be a highly promising approach to engineer the optical and electronic properties of the existing materials or even endow them with unexpected properties. Surface structure engineering has witnessed the breakthrough in increasing the photocatalytic efficiency of TiO2 nanomaterials by creating a defect-rich or amorphous surface layer with black color and extension of optical absorption to the whole visible spectrum, along with markedly enhanced photocatalytic activities. In this review, the recent progress in the development of black TiO2 nanomaterials is reviewed to gain a better understanding of the structure-property relationship with the consideration of preparation methods and to project new insights into the future development of black TiO2 nanomaterials in photocatalytic applications.

  17. Investigating the Relationship between Test Preparation and "TOEFL iBT"® Performance. Research Report. ETS RR-14-15

    Science.gov (United States)

    Liu, Ou Lydia

    2014-01-01

    This study investigates the relationship between test preparation and test performance on the "TOEFL iBT"® exam. Information on background variables and test preparation strategies was gathered from 14,593 respondents in China through an online survey. A Chinese standardized English test was used as a control for prior English ability.…

  18. Influence of PVP in magnetic properties of NiSn nanoparticles prepared by polyol method

    Energy Technology Data Exchange (ETDEWEB)

    Bobadilla, L.F., E-mail: lbobadilla@iciq.es [Departamento de Quimica Inorganica e Instituto de Ciencia de Materiales, Centro mixto Universidad de Sevilla-CSIC, Av. Americo Vespucio, 41092 Sevilla (Spain); Garcia, C. [Physics Department, Bogazici University, North Campus KB 331-O, Bebek/Istambul (Turkey); Delgado, J.J. [Departamento de Ciencia de los Materiales e Ingenieria Metalurgica y Quimica Inorganica, Facultad de Ciencias, Universidad de Cadiz, Campus Rio San Pedro, E-11510 Puerto Real, Cadiz (Spain); Sanz, O. [Grupo de Ingenieria Quimica, Departamento de Quimica Aplicada, Facultad de Ciencias Quimicas, UPV/EHU, Paseo Manuel de Lardizabal, 3, 20018 San Sebastian (Spain); Romero-Sarria, F.; Centeno, M.A.; Odriozola, J.A. [Departamento de Quimica Inorganica e Instituto de Ciencia de Materiales, Centro mixto Universidad de Sevilla-CSIC, Av. Americo Vespucio, 41092 Sevilla (Spain)

    2012-11-15

    The influence of PVP on the magnetic properties of NiSn nanoparticles prepared by polyol method has been studied. NiSn nanoparticles exhibit superparamagnetic behavior although there is a ferromagnetic contribution due to particles agglomerated below the blocking temperature. The particle size is controlled by the addiction of PVP in varying amounts. The addition of PVP also favours the particles isolation, narrow the particle size distribution and decrease the interparticle interaction strength increasing the superparamagnetic contribution. - Highlights: Black-Right-Pointing-Pointer Ni{sub x}Sn{sub y} alloys nanoparticles have been prepared by polyol method. Black-Right-Pointing-Pointer NiSn nanoparticles exhibit superparamagnetic behavior. Black-Right-Pointing-Pointer The PVP addition favours the particles isolation.

  19. Physicochemical and antioxidative properties of black, brown and red rice varieties of northern Thailand

    Directory of Open Access Journals (Sweden)

    Noppawat Pengkumsri

    2015-06-01

    Full Text Available Rice, the seed of Oryza species, is the major cereal crop in most of the developing countries. Nearly 95% of global rice production is done in Asian countries, and about half of the world’s population consumes it. Some speciality rices are not commonly consumed. Colored rice is one of such variety. In these varieties, high amounts of anthocyanin pigment are deposited in the rice coat to form its black (also known as purple, brown and red colors. Minimum studies are there to explain the properties of these rice varieties of Thailand. Thus, the current study was aimed to assess the physicochemical and antioxidative properties of three rice varieties (Chiang Mai Black rice, Mali Red rice and Suphanburi-1 Brown rice of different cultivars of northern Thailand. Rice bran extracts of these three cultivars were prepared with different solvents (polar and non-polar for the evaluation of total phytochemical content and anti-oxidant free-radical-scavenging properties. Chiang Mai Black rice contained higher concentration of phenolic acid, flavonoids, and anthocyanins (Cyanidin 3-glucoside, peonidin 3-glucoside, cyanidin chloride. Chiang Mai Black rice is richer in free-radical-scavenging compounds and activities than the other tested varieties. Polar extractions of rice bran are high in anti-oxidative compounds and activities than non-polar extractions.

  20. Spectroscopy of Kerr Black Holes with Earth- and Space-Based Interferometers.

    Science.gov (United States)

    Berti, Emanuele; Sesana, Alberto; Barausse, Enrico; Cardoso, Vitor; Belczynski, Krzysztof

    2016-09-02

    We estimate the potential of present and future interferometric gravitational-wave detectors to test the Kerr nature of black holes through "gravitational spectroscopy," i.e., the measurement of multiple quasinormal mode frequencies from the remnant of a black hole merger. Using population synthesis models of the formation and evolution of stellar-mass black hole binaries, we find that Voyager-class interferometers will be necessary to perform these tests. Gravitational spectroscopy in the local Universe may become routine with the Einstein Telescope, but a 40-km facility like Cosmic Explorer is necessary to go beyond z∼3. In contrast, detectors like eLISA (evolved Laser Interferometer Space Antenna) should carry out a few-or even hundreds-of these tests every year, depending on uncertainties in massive black hole formation models. Many space-based spectroscopical measurements will occur at high redshift, testing the strong gravity dynamics of Kerr black holes in domains where cosmological corrections to general relativity (if they occur in nature) must be significant.

  1. In what sense a neutron star-black hole binary is the holy grail for testing gravity?

    International Nuclear Information System (INIS)

    Bagchi, Manjari; Torres, Diego F.

    2014-01-01

    Pulsars in binary systems have been very successful to test the validity of general relativity in the strong field regime [1-4]. So far, such binaries include neutron star-white dwarf (NS-WD) and neutron star-neutron star (NS-NS) systems. It is commonly believed that a neutron star-black hole (NS-BH) binary will be much superior for this purpose. But in what sense is this true? Does it apply to all possible deviations?

  2. Stress, coping, and depression: testing new hypotheses in a prospectively studied general population sample of U.S. born Whites and Blacks

    Science.gov (United States)

    Keyes, K.M.; Barnes, D.; Bates, L.M.

    2010-01-01

    The scarcity of empirically supported explanations for the Black/White prevalence difference in depression in the U.S. is a conspicuous gap in the literature. Recent evidence suggests that the paradoxical observation of decreased risk of depression but elevated rates of physical illness among Blacks in the U.S. compared with Whites may be accounted for by the use of coping behaviors (e.g., alcohol and nicotine consumption, overeating) among Blacks exposed to high stress levels. Such coping behaviors may mitigate deleterious effects of stressful exposures on mental health while increasing the risk of physical ailments. The racial patterning in mental and physical health outcomes could therefore be explained by this mechanism if a) these behaviors were more prevalent among Blacks than Whites and/or b) the effect of these behavioral responses to stress was differential by race. The present study challenges this hypothesis using longitudinal, nationally-representative data with comprehensive DSM-IV diagnoses. Data are drawn from 34,653 individuals sampled in Waves 1 (2001-2002) and 2 (2004-2005) as part of the US National Epidemiologic Survey on Alcohol and Related Conditions. Results showed that a) Blacks were less likely to engage in alcohol or nicotine consumption at low, moderate, and high levels of stress compared to Whites, and b) there was a significant three-way interaction between race, stress, and coping behavior for BMI only (F=2.11, df=12, p=0.03), but, contrary to the hypothesis, elevated BMI was protective against depression in Blacks at low, not high, levels of stress. Further, engagement in unhealthy behaviors, especially at pathological levels, did not protect against depression in Blacks or in Whites. In sum, the impact of stress and coping processes on depression do not appear to operate differently in Blacks versus Whites. Further research testing innovative hypotheses that would explain the difference in Black/White depression prevalence is

  3. Influence of Specimen Preparation and Test Methods on the Flexural Strength Results of Monolithic Zirconia Materials.

    Science.gov (United States)

    Schatz, Christine; Strickstrock, Monika; Roos, Malgorzata; Edelhoff, Daniel; Eichberger, Marlis; Zylla, Isabella-Maria; Stawarczyk, Bogna

    2016-03-09

    The aim of this work was to evaluate the influence of specimen preparation and test method on the flexural strength results of monolithic zirconia. Different monolithic zirconia materials (Ceramill Zolid (Amann Girrbach, Koblach, Austria), Zenostar ZrTranslucent (Wieland Dental, Pforzheim, Germany), and DD Bio zx² (Dental Direkt, Spenge, Germany)) were tested with three different methods: 3-point, 4-point, and biaxial flexural strength. Additionally, different specimen preparation methods were applied: either dry polishing before sintering or wet polishing after sintering. Each subgroup included 40 specimens. The surface roughness was assessed using scanning electron microscopy (SEM) and a profilometer whereas monoclinic phase transformation was investigated with X-ray diffraction. The data were analyzed using a three-way Analysis of Variance (ANOVA) with respect to the three factors: zirconia, specimen preparation, and test method. One-way ANOVA was conducted for the test method and zirconia factors within the combination of two other factors. A 2-parameter Weibull distribution assumption was applied to analyze the reliability under different testing conditions. In general, values measured using the 4-point test method presented the lowest flexural strength values. The flexural strength findings can be grouped in the following order: 4-point strength values than prepared before sintering. The Weibull moduli ranged from 5.1 to 16.5. Specimens polished before sintering showed higher surface roughness values than specimens polished after sintering. In contrast, no strong impact of the polishing procedures on the monoclinic surface layer was observed. No impact of zirconia material on flexural strength was found. The test method and the preparation method significantly influenced the flexural strength values.

  4. Analytical support for the preparation of bundle test QUENCH-10 on air ingress

    International Nuclear Information System (INIS)

    Birchley, J.; Haste, T.; Homann, C.; Hering, W.

    2005-07-01

    Bundle test QUENCH-10 is dedicated to study air ingress with subsequent water quench during a supposed accident in a spent fuel storage tank. It was proposed by AEKI, Budapest, Hungary and was performed on 21 July 2004 in the QUENCH facility at Forschungszentrum Karlsruhe. Preparation of the test is based on common analytical work at Forschungszentrum Karlsruhe and Paul Scherrer Institut, Villigen, Switzerland, mainly with the severe accident codes SCDAP/RELAP5 and MELCOR, to derive the protocol for the essential test phases, namely pre-oxidation, air ingress and quench phase. For issues that could not be tackled by this computational work, suggestions for the test conduct were made and applied during the test. Improvements of the experimental set-up and the test conduct were suggested and largely applied. In SCDAP/RELAP5, an error was found: for thick oxide scales, the output value of the oxide scale is sensibly underestimated. For the aims of the test preparation, its consequences could be taken into account. Together with the related computational and other analytical support by the engaged institutions the test is co-financed as test QUENCH-L1 by the European Community under the Euratom Fifth Framework Programme on Nuclear Fission Safety 1998 - 2002 (LACOMERA Project, contract No. FIR1-CT2002-40158). (orig.)

  5. Nonlinear evolutions of bosonic clouds around black holes

    International Nuclear Information System (INIS)

    Okawa, Hirotada

    2015-01-01

    Black holes are a laboratory not only for testing the theory of gravity but also for exploring the properties of fundamental fields. Fundamental fields around a supermassive black hole give rise to extremely long-lived quasi-bound states which can in principle extract the energy and angular momentum from the black hole. To investigate the final state of such a system, the backreaction onto the spacetime becomes important because of the nonlinearity of the Einstein equation. In this paper, we review the numerical method to trace the evolution of massive scalar fields in the vicinity of black holes, how such a system originates from scalar clouds initially in the absence of black holes or from the capture of scalar clouds by a black hole, and the evolution of quasi-bound states around both a non-rotating black hole and a rotating black hole including the backreaction. (paper)

  6. Preparation and characterization of chitosan/genipin/poly(N-vinyl-2-pyrrolidone) films for controlled release drugs

    Energy Technology Data Exchange (ETDEWEB)

    Aldana, Ana Agustina, E-mail: aaldana@fcq.unc.edu.ar [Departamento de Quimica Organica, Facultad de Ciencias Quimicas, Universidad Nacional de Cordoba (UNC), Edificio de Ciencias II, Medina Allende y Haya de la Torre, Ciudad Universitaria, Cordoba 5000 (Argentina); Gonzalez, Agustin, E-mail: agustingonzalez@fcq.unc.edu.ar [Departamento de Quimica Organica, Facultad de Ciencias Quimicas, Universidad Nacional de Cordoba (UNC), Edificio de Ciencias II, Medina Allende y Haya de la Torre, Ciudad Universitaria, Cordoba 5000 (Argentina); Strumia, Miriam C., E-mail: mcs@fcq.unc.edu.ar [Departamento de Quimica Organica, Facultad de Ciencias Quimicas, Universidad Nacional de Cordoba (UNC), Edificio de Ciencias II, Medina Allende y Haya de la Torre, Ciudad Universitaria, Cordoba 5000 (Argentina); Martinelli, Marisa, E-mail: mmartinelli@fcq.unc.edu.ar [Departamento de Quimica Organica, Facultad de Ciencias Quimicas, Universidad Nacional de Cordoba (UNC), Edificio de Ciencias II, Medina Allende y Haya de la Torre, Ciudad Universitaria, Cordoba 5000 (Argentina)

    2012-05-15

    Highlights: Black-Right-Pointing-Pointer Cross-linked chitosan films using genipin and/or PVP. Black-Right-Pointing-Pointer Propranolol hydrochloride was used like a model drug to release studies. Black-Right-Pointing-Pointer Incorporating PVP improves mechanical and diffusion properties. Black-Right-Pointing-Pointer Ch-Gen 0.10% and Ch-Gen 0.10%-PVP have optimal behavior. - Abstract: The study of the physicochemical and functional properties of chitosan films cross-linked with genipin and poly(N-vinyl-2-pyrrolidone) (PVP) was performed in this work. Cross-linked films were prepared by casting method from acetic acid solutions. The structure and physical properties of the films were analyzed by infrared spectroscopy (FT-IR), nuclear magnetic resonance spectroscopy ({sup 13}C NMR), differential scanning calorimetry (DSC) and mechanical testings. Propranolol hydrochloride was used like a model drug to determine the behavior of drug release from films. The drug release capacity was measured and compared with the degree of cross-linking, mechanical properties and swelling index. There was an appropriate balance of hydrophilicity, mechanical properties and diffusion by the incorporation of PVP into the networks cross-linked with genipin. The combination of both cross-linkers allows obtaining a soft and tough material potentially applicable as a controlled release. This research represents the first report where both cross-linkers, chemical and ionic agents, are used for obtaining films. These studies suggest that the chitosan films prepared here are promising drug delivery systems for buccal application, with thermal stability and acceptable mechanical properties. Buccal films may be preferred in terms of flexibility and comfort.

  7. Black-hole astrophysics

    Energy Technology Data Exchange (ETDEWEB)

    Bender, P. [Univ. of Colorado, Boulder, CO (United States); Bloom, E. [Stanford Linear Accelerator Center, Menlo Park, CA (United States); Cominsky, L. [Sonoma State Univ., Rohnert Park, CA (United States). Dept. of Physics and Astronomy] [and others

    1995-07-01

    Black-hole astrophysics is not just the investigation of yet another, even if extremely remarkable type of celestial body, but a test of the correctness of the understanding of the very properties of space and time in very strong gravitational fields. Physicists` excitement at this new prospect for testing theories of fundamental processes is matched by that of astronomers at the possibility to discover and study a new and dramatically different kind of astronomical object. Here the authors review the currently known ways that black holes can be identified by their effects on their neighborhood--since, of course, the hole itself does not yield any direct evidence of its existence or information about its properties. The two most important empirical considerations are determination of masses, or lower limits thereof, of unseen companions in binary star systems, and measurement of luminosity fluctuations on very short time scales.

  8. One-Loop Test of Quantum Black Holes in anti-de Sitter Space

    Science.gov (United States)

    Liu, James T.; Pando Zayas, Leopoldo A.; Rathee, Vimal; Zhao, Wenli

    2018-06-01

    Within 11-dimensional supergravity we compute the logarithmic correction to the entropy of magnetically charged asymptotically AdS4 black holes with arbitrary horizon topology. We find perfect agreement with the expected microscopic result arising from the dual field theory computation of the topologically twisted index. Our result relies crucially on a particular limit to the extremal black hole case and clarifies some aspects of quantum corrections in asymptotically AdS spacetimes.

  9. Development of resistance welding process. 4. Preparation of pressuring enclosed creep test specimen of 7A material

    International Nuclear Information System (INIS)

    Endo, Hideo; Seki, Masayuki; Ishibashi, Fujio; Hirako, Kazuhito; Tsukada, Tatsuya

    2001-02-01

    Mechanical strength in the position welded by resistance welding system was examined in 1999. The test specimens were destroyed in the welding position in a shorter time than expected in the creep test. Therefore, test specimens were prepared to evaluate the cause of destruction. Inner-pressure enclosed creep test specimens were prepared by resistance welding method. Cladding material with low deviation of thickness and high re-crystallization rate was used. Heat treatment after resistance welding was performed to remove the influence of residual stress and the precipitation of carbides. (1) Before preparation of specimens, the welding condition was fixed. Three test specimens were prepared. Two specimens without heat treatment were transported to MMS in Oarai Engineering Center on Aug. 4, 2000. One specimen with heat treatment was transported to MMS after evaluating the residual stress to get optimum heat treatment condition. (2) Specimens were prepared with welding end plugs to both ends of ferritic ODS cladding. Enclosing sides were welded with highly strong Ferritic/Martensitic steel end plugs. The other sides were welded with ferritic ODS end plugs. (3) Some kinds of electrical wave data were obtained during performing welding. Welding position was evaluated with supersonic detector after performing welding. (4) Mechanical strength of welding position in high temperature 800degC was confirmed to be equal to or larger than that of cladding material. The highly qualified specimens in the present were successfully prepared. (author)

  10. Classical and quantum gravity of brane black holes

    International Nuclear Information System (INIS)

    Gregory, Ruth; Ross, Simon F.; Zegers, Robin

    2008-01-01

    We test the holographic conjecture of brane black holes: that a full classical 5D solution will correspond to a quantum corrected 4D black hole. Using the Schwarzschild-AdS black string, we compare the braneworld back reaction at strong coupling with the calculation of the quantum stress tensor on Schwarzschild-AdS 4 at weak coupling. The two calculations give different results and provide evidence that the stress tensor at strong coupling is indeed different to the weak coupling calculations, and hence does not conform to our notion of a quantum corrected black hole. We comment on the implications for an asymptotically flat black hole.

  11. Cosmic censorship of rotating Anti-de Sitter black hole

    Energy Technology Data Exchange (ETDEWEB)

    Gwak, Bogeun; Lee, Bum-Hoon, E-mail: rasenis@sogang.ac.kr, E-mail: bhl@sogang.ac.kr [Center for Quantum Spacetime, Sogang University, Seoul 04107 (Korea, Republic of)

    2016-02-01

    We test the validity of cosmic censorship in the rotating anti-de Sitter black hole. For this purpose, we investigate whether the extremal black hole can be overspun by the particle absorption. The particle absorption will change the mass and angular momentum of the black hole, which is analyzed using the Hamilton-Jacobi equations consistent with the laws of thermodynamics. We have found that the mass of the extremal black hole increases more than the angular momentum. Therefore, the outer horizon of the black hole still exists, and cosmic censorship is valid.

  12. Cosmic censorship of rotating Anti-de Sitter black hole

    International Nuclear Information System (INIS)

    Gwak, Bogeun; Lee, Bum-Hoon

    2016-01-01

    We test the validity of cosmic censorship in the rotating anti-de Sitter black hole. For this purpose, we investigate whether the extremal black hole can be overspun by the particle absorption. The particle absorption will change the mass and angular momentum of the black hole, which is analyzed using the Hamilton-Jacobi equations consistent with the laws of thermodynamics. We have found that the mass of the extremal black hole increases more than the angular momentum. Therefore, the outer horizon of the black hole still exists, and cosmic censorship is valid

  13. Introduction to General Relativity and Black Holes (5/5)

    CERN Multimedia

    CERN. Geneva

    2001-01-01

    Conceptual foundations of General Relativity (GR). Uniqueness of GR. Mathematical framework: tensor calculus, Riemannian geometry, connection, 'spin' connection, curvature, Cartan's form calculus. Hilbert-Einstein action, Einstein equations. Weak gravitational fields. Post Newtonian Approximation. Gravitanional Waves. Exact solutions. Killing vectors. Experimental tests. Black Holes: extensions of the Schwarzschild solution; Kerr-Newman holes; no-hair theorems; energtics of black holes; the membrane approach; quantum mechanics of black holes; Bekenstein entropy; Hawking temperature; black holes and string theory.

  14. Introduction to General Relativity and Black Holes (3/5)

    CERN Multimedia

    CERN. Geneva

    2001-01-01

    Conceptual foundations of General Relativity (GR). Uniqueness of GR. Mathematical framework: tensor calculus, Riemannian geometry, connection, 'spin' connection, curvature, Cartan's form calculus. Hilbert-Einstein action, Einstein equations. Weak gravitational fields. Post Newtonian Approximation. Gravitanional Waves. Exact solutions. Killing vectors. Experimental tests. Black Holes: extensions of the Schwarzschild solution; Kerr-Newman holes; no-hair theorems; energtics of black holes; the membrane approach; quantum mechanics of black holes; Bekenstein entropy; Hawking temperature; black holes and string theory.

  15. Introduction to General Relativity and Black Holes (1/5)

    CERN Multimedia

    CERN. Geneva

    2001-01-01

    Conceptual foundations of General Relativity (GR). Uniqueness of GR. Mathematical framework: tensor calculus, Riemannian geometry, connection, 'spin' connection, curvature, Cartan's form calculus. Hilbert-Einstein action, Einstein equations. Weak gravitational fields. Post Newtonian Approximation. Gravitanional Waves. Exact solutions. Killing vectors. Experimental tests. Black Holes: extensions of the Schwarzschild solution; Kerr-Newman holes; no-hair theorems; energtics of black holes; the membrane approach; quantum mechanics of black holes; Bekenstein entropy; Hawking temperature; black holes and string theory.

  16. Introduction to General Relativity and Black Holes (2/5)

    CERN Multimedia

    CERN. Geneva

    2001-01-01

    Conceptual foundations of General Relativity (GR). Uniqueness of GR. Mathematical framework: tensor calculus, Riemannian geometry, connection, 'spin' connection, curvature, Cartan's form calculus. Hilbert-Einstein action, Einstein equations. Weak gravitational fields. Post Newtonian Approximation. Gravitanional Waves. Exact solutions. Killing vectors. Experimental tests. Black Holes: extensions of the Schwarzschild solution; Kerr-Newman holes; no-hair theorems; energtics of black holes; the membrane approach; quantum mechanics of black holes; Bekenstein entropy; Hawking temperature; black holes and string theory.

  17. Introduction to General Relativity and Black Holes (4/5)

    CERN Multimedia

    CERN. Geneva

    2001-01-01

    Conceptual foundations of General Relativity (GR). Uniqueness of GR. Mathematical framework: tensor calculus, Riemannian geometry, connection, 'spin' connection, curvature, Cartan's form calculus. Hilbert-Einstein action, Einstein equations. Weak gravitational fields. Post Newtonian Approximation. Gravitanional Waves. Exact solutions. Killing vectors. Experimental tests. Black Holes: extensions of the Schwarzschild solution; Kerr-Newman holes; no-hair theorems; energtics of black holes; the membrane approach; quantum mechanics of black holes; Bekenstein entropy; Hawking temperature; black holes and string theory.

  18. Exploring biomass based carbon black as filler in epoxy composites: Flexural and thermal properties

    International Nuclear Information System (INIS)

    Abdul Khalil, H.P.S.; Firoozian, P.; Bakare, I.O.; Akil, Hazizan Md.; Noor, Ahmad Md.

    2010-01-01

    Carbon blacks (CB), derived from bamboo stem (BS-CB), coconut shells (CNS-CB) and oil palm empty fiber bunch (EFB-CB), were obtained by pyrolysis of fibers at 700 o C, characterized and used as filler in epoxy composites. The results obtained showed that the prepared carbon black possessed well-developed porosities and are predominantly made up of micropores. The BS-CB, CNS-CB and EFB-CB filled composites were prepared and characterized using scanning electron microscope (SEM) and thermogravimetric analyzer (TGA). The SEM showed that the fractured surface of the composite indicates its high resistance to fracture. The CBs-epoxy composites exhibited better flexural properties than the neat epoxy, which was attributed to better adhesion between the CBs and the epoxy resin. TGA showed that there was improvement in thermal stability of the carbon black filled composites compared to the neat epoxy resin.

  19. Testing effective string models of black holes with fixed scalars

    International Nuclear Information System (INIS)

    Krasnitz, M.; Klebanov, I.R.

    1997-01-01

    We solve the problem of mixing between the fixed scalar and metric fluctuations. First, we derive the decoupled fixed scalar equation for the four-dimensional black hole with two different charges. We proceed to the five-dimensional black hole with different electric (one-brane) and magnetic (five-brane) charges, and derive two decoupled equations satisfied by appropriate mixtures of the original fixed scalar fields. The resulting greybody factors are proportional to those that follow from coupling to dimension (2,2) operators on the effective string. In general, however, the string action also contains couplings to chiral operators of dimension (1,3) and (3,1), which cause disagreements with the semiclassical absorption cross sections. Implications of this for the effective string models are discussed. copyright 1997 The American Physical Society

  20. Dance of Two Monster Black Holes

    Science.gov (United States)

    Kohler, Susanna

    2016-03-01

    This past December, researchers all over the world watched an outburst from the enormous black hole in OJ 287 an outburst that had been predicted years ago using the general theory of relativity.Outbursts from Black-Hole OrbitsOJ 287 is one of the largest supermassive black holes known, weighing in at 18 billion solar masses. Located about 3.5 billion light-years away, this monster quasar is bright enough that it was first observed as early as the 1890s. What makes OJ 287 especially interesting, however, is that its light curve exhibits prominent outbursts roughly every 12 years.Diagram illustrating the orbit of the secondary black hole (shown in blue) in OJ 287 from 2000 to 2023. We see outbursts (the yellow bubbles) every time the secondary black hole crosses the accretion disk (shown in red, ina side view) surrounding the primary (the black circle). [Valtonen et al. 2016]What causes the outbursts? Astronomers think that there is a second supermassive black hole, ~100 times smaller, inspiraling as it orbits the central monster and set to merge within the next 10,000 years. In this model, the primary black hole of OJ 287 is surrounded by a hot accretion disk. As the secondary black hole orbits the primary, it regularly punches through this accretion disk, heating the material and causing the release of expanding bubbles of hot gas pulled from the disk. This gas then radiates thermally, causing the outbursts we see.Attempts to model this scenario using Newtonian orbits all fail; the timing of the secondary black holes crossings through the accretion disk (as measured by when we see the outbursts) can only be explained by a model incorporating general-relativistic effects on the orbit. Careful observations and precise timing of these outbursts therefore provide an excellent test of general relativity.Watching a Predicted CrossingThe model of OJ 287 predicted another disk crossing in December 2015, so professional and amateur astronomers around the world readied more

  1. Guide of Black granite prospect ion for the department of Florida

    International Nuclear Information System (INIS)

    Bossi, J.; Campal, N.

    1989-01-01

    The black granite prospection project is between the government of Canada and Uruguay agreement (Facultad de Agronomia - Universidad de la Republica). The main objective is the location and mapping of black granite veins to obtain potential deposits. The study of the relations between surface and deep features of these veins. The preparation of a guide to exploration and exploitation plan for mining companies. Reinforce the capacity of research in economic geology as well as increasing the exports by resources jobs

  2. Preparation, Conduct and Evaluation of Exercises to Test Preparedness for a Nuclear or Radiological Emergency - Training Materials

    International Nuclear Information System (INIS)

    2010-01-01

    Emergency response exercises are a key component of a good program of preparation in emergencies. They can provide a unique insight on the State of preparation of emergency response organizations. They can also be the basis for continuous improvement programs of the infrastructure of response in emergencies. However, to be more useful, the exercises in emergency response need to be well organized, professionally conducted and its assessment should focus on the potential for constructive improvement. The course of the IAEA on preparedness, conduction and evaluation exercises to test the preparation before a nuclear emergency or radiation designed for people and organizations that want to increase their ability to carry out effective and significant emergency exercises. The objectives of this course are: To familiarize participants with concepts, terminology, process of preparation, conduction and evaluation of the exercise to test the preparation before a nuclear emergency or radiation; Provide participants with knowledge practical and the ability to organize, lead and evaluate an exercise to test the preparation for a nuclear emergency or radiation in their own countries; Submit an exercise response model in emergency prepared by the IAEA; and give participants the skill to adapt the proposal of model exercise and organize and lead this exercise model right in your own country. [es

  3. THE EFFECT OF WATER EXTRACTS FROM WINTER SAVORY ON BLACK BEAN APHID MORTALITY

    Directory of Open Access Journals (Sweden)

    Milena Rusin

    2016-01-01

    Full Text Available The aim of this study was to determine the effect of water extracts prepared from fresh and dry matter of winter savory (Satureja montana L. on mortality of wingless females and larvae of black bean aphid (Aphis fabae Scop.. The experiment was conducted in the laboratory, in six replicates. Dry extracts were prepared at concentration of 2%, 5% and 10%, while the fresh plant at concentration of 10%, 20% and 30%. Stomach poisoning of extracts was determined by soaking broad bean leaves in the respective solutions, and then determining mortality of wingless female and larvae feeding on leaves thus prepared at 12 hour intervals. The results of the experiment showed that the extract prepared from dry matter at the highest concentration (10%, as well as the extracts from fresh matter at concentration of 20% and 30% contributed to an increase in mortality of wingless female of black bean aphid. Meanwhile, extracts prepared from both dry and fresh matter at two highest concentrations caused an increase in mortality of larvae of this pest. Furthermore, with increasing concentrations of analysed extracts prepared from both fresh and dry matter of winter savory, their negative effect on wingless females and larvae usually increase.

  4. The PZC-based Tc-99m generator preparation and its performance test

    International Nuclear Information System (INIS)

    Liu Yishu

    2007-01-01

    This paper described the preparation of Tc-99m generator prepared with Japan distributing Mo adsorbent PZC and irradiated nature MoO 3 and its performance test. Four Tc-99m generators were prepared with different batches of PZC and reactor irradiated nature MoO 3 . The adsorption capacity of PZC to Mo is approximately 200mgMo/gPZC. The adsorption efficiency of three batches PZC is good (>90%) and that of one batch of PZC is not good enough (∼83%). The loss of fine powder (The PZC is fragile) is quite different with the different preparation process of PZC. The elution efficiency is 80-90% and has the up trend with the elution date. The Mo breakthrough can be controlled to acceptable level by connecting HZO safe column containing 1.0g HZO. All the specifications of eluted from PZC-based Tc-99m generator can meet the requirements under Sodium Pertechnetate injection in China Pharmacopoeia. (author)

  5. Seedling-sapling growth variation in a southern Illinios black walnut provenance/progeny test

    Science.gov (United States)

    George Rink; J. W. Van Sambeek

    1987-01-01

    Nursery root and shoot measurements and annual height, basal diameter and survival data for the 5 years after outplanting were used to describe black walnut growth variation in southern Illinois. At age 5 sapling height narrow-sense heritability was found to be 0.49 for 131 open-pollinated families from across the black walnut comercial range. Greatest height and...

  6. Black Silicon Solar Cells with Black Ribbons

    DEFF Research Database (Denmark)

    Davidsen, Rasmus Schmidt; Tang, Peter Torben; Mizushima, Io

    2016-01-01

    We present the combination of mask-less reactive ion etch (RIE) texturing and blackened interconnecting ribbons as a method for obtaining all-black solar panels, while using conventional, front-contacted solar cells. Black silicon made by mask-less reactive ion etching has total, average...... in the range 15.7-16.3%. The KOH-textured reference cell had an efficiency of 17.9%. The combination of black Si and black interconnecting ribbons may result in aesthetic, all-black panels based on conventional, front-contacted silicon solar cells....... reflectance below 0.5% across a 156x156 mm2 silicon (Si) wafer. Black interconnecting ribbons were realized by oxidizing copper resulting in reflectance below 3% in the visible wavelength range. Screen-printed Si solar cells were realized on 156x156 mm2 black Si substrates with resulting efficiencies...

  7. Proteolytic activity of selected moulds in the first fermentation of black-seeded soysauce

    Science.gov (United States)

    Yulifianti, R.; Ginting, E.

    2018-01-01

    Black-seeded soybean is preferred as normally it has higher protein content and would give black colour to the soyfiltrate for making soysauce. Mould is usually used in the first fermentation of soysauce making to prepare koji with high soluble protein as a media for the subsequent bacteria fermentation in brine solution. Black-seeded soybean of Detam 1 variety was used as the soysauce ingredient. The trial was a randomized complete design with four replicates. The treatments were (1) Rhizopus oligosporus starter (in flour form) with two day-fermentation, (2) similar R. oligosporus starter with three-day fermentation, (3) Aspergillus sojae (pure culture) with three-day fermentation and (4) A. sojae in flour form with three-day fermentation. The black-seeded soybean had 100-grain weight of 11.7 g, high protein content of 42.5% dw and fat content of 14.9% dw. Koji prepared using R. oligosporus starter with two-day fermentation had the lowest protein content (48.9% dw). Both starters of A. sojae culture and flour gave the highest soluble protein content of koji (41.0-41.5% dw), followed by R. oligosporus starter with 3 day-fermentation (35.2% dw). Whilst the lowest value was noted in koji prepared using R. oligosporus starter with two day-fermentation (30.8% dw). This suggests that both A. sojae starters had similar proteolitic activity and higher than that of R. oligosporus starter. In terms of practical application and maintenance of the mould viability by soysauce processors, the use of A. sojae flour starter with three-day fermentation is suggested.

  8. Measuring the Pros and Cons of What It Means to Be a Black Man: Development and Validation of the Black Men's Experiences Scale (BMES).

    Science.gov (United States)

    Bowleg, Lisa; English, Devin; Del Rio-Gonzalez, Ana Maria; Burkholder, Gary J; Teti, Michelle; Tschann, Jeanne M

    2016-04-01

    Although extensive research documents that Black people in the U.S. frequently experience social discrimination, most of this research aggregates these experiences primarily or exclusively by race. Consequently, empirical gaps exist about the psychosocial costs and benefits of Black men's experiences at the intersection of race and gender. Informed by intersectionality, a theoretical framework that highlights how multiple social identities intersect to reflect interlocking social-structural inequality, this study addresses these gaps with the qualitative development and quantitative test of the Black Men's Experiences Scale (BMES). The BMES assesses Black men's negative experiences with overt discrimination and microaggressions, as well their positive evaluations of what it means to be Black men. First, we conducted focus groups and individual interviews with Black men to develop the BMES. Next, we tested the BMES with 578 predominantly low-income urban Black men between the ages of 18 and 44. Exploratory factor analysis suggested a 12-item, 3-factor solution that explained 63.7% of the variance. We labeled the subscales: Overt Discrimination, Microaggressions, and Positives: Black Men . Confirmatory factor analysis supported the three-factor solution. As hypothesized, the BMES's subscales correlated with measures of racial discrimination, depression, resilience, and social class at the neighborhood-level. Preliminary evidence suggests that the BMES is a reliable and valid measure of Black men's experiences at the intersection of race and gender.

  9. Recent advances on bioactivities of black rice.

    Science.gov (United States)

    Dias, Aécio L de S; Pachikian, Barbara; Larondelle, Yvan; Quetin-Leclercq, Joëlle

    2017-11-01

    Black rice has been consumed for centuries in Asian countries such as China, Korea or Japan. Nowadays, extracts and derivatives are considered as beneficial functional foods because of their high content in several bioactive molecules such as anthocyanins, other phenolics and terpenoids. The purpose of this review is to summarize and discuss recent developments on black rice bioactivities. Some sterols and triterpenoids with potential anticancer properties already tested in vitro and in vivo have been isolated and identified from bran extracts of black rice. Protection against osteoporosis has been suggested for the first time for black rice extracts. Because of its antioxidant and anti-inflammatory properties, black rice also protects liver and kidney from injuries. One clinical study reported the interest of black rice in case of alcohol withdrawal. Several advances have been recently achieved on the understanding of the potential biological effects of black rice and its derivatives. They further confirm that black rice should be considered as a promising source of health-promoting functional foods targeting a large set of noninfectious diseases. However, more clinical studies are needed to support the findings highlighted in this review.

  10. Sensing of environmental pollutant by conductive composite from prepared from hyperbranched polymer-grafted carbon black and crystalline polymer

    International Nuclear Information System (INIS)

    Taniguchi, Y.; Chen, J.; Ogawa, M.; Yokoyama, K.; Shimizu, H.; Tsubokawa, N.; Maekawa, Y.; Yoshida, M.

    2002-01-01

    Complete text of publication follows. The hyperbranched (HB) polymer-grafted (PG) carbon blacks (CB) have the possibility of utilizing as a support of catalyst and enzyme, and a curing agent of epoxy resin, because they have much terminal amino or hydroxyl groups. The postgrafting of crystalline polymer onto HB PG CB and the sensing of environmental pollutant by the conductive composite prepared from the polymer-postgrafted CB was discussed. The grafting of poly(amidoamide) onto CB surface was achieved by repeating either Michael addition of methyl acrylate to amino group on the surface or the amidation of the resulting terminal methyl ester group with ethylene diamine. HB polyester onto CB surface was grafted by stepwise growth of 2,2-bis(hydroxymethyl)propionic acid (bis-MPA) from surface carboxyl and hydroxyl groups on CB as a core in the presence of p-toluenesulfonic acid (p-TSA). The one-pot grafting of HB polyester onto CB as core was also achieved by the polycondensation of bis-MPA in the presence of p-TSA. Postgrafting of crystalline polymer onto HB polymer-grafted CB was achieved by the reaction of terminal amino or hydroxyl groups of grafted chain with COCl-terminated crystalline polymer. The electric resistance of the composite prepared from crystalline polymer-postgrafted CB was found to increase drastically in hexane, containing environmental pollutant, such as chloroform and trichloroethane, and returned immediately to the initial resistance when it was transferred into pure hexane. Based on the above results, it is concluded that the composite can be used as a novel sensor for environmental pollutant in solution

  11. Bringing Black Holes Home

    Science.gov (United States)

    Furmann, John M.

    2003-03-01

    Black holes are difficult to study because they emit no light. To overcome this obstacle, scientists are trying to recreate a black hole in the laboratory. The article gives an overview of the theories of Einstein and Hawking as they pertain to the construction of the Large Hadron Collider (LHC) near Geneva, Switzerland, scheduled for completion in 2006. The LHC will create two beams of protons traveling in opposing directions that will collide and create a plethora of scattered elementary particles. Protons traveling in opposite directions at very high velocities may create particles that come close enough to each other to feel their compacted higher dimensions and create a mega force of gravity that can create tiny laboratory-sized black holes for fractions of a second. The experiments carried out with LHC will be used to test modern string theory and relativity.

  12. How bees distinguish black from white

    Directory of Open Access Journals (Sweden)

    Horridge A

    2014-10-01

    Full Text Available Adrian Horridge Biological Sciences, Australian National University, Canberra, ACT, AustraliaAbstract: Bee eyes have photoreceptors for ultraviolet, green, and blue wavelengths that are excited by reflected white but not by black. With ultraviolet reflections excluded by the apparatus, bees can learn to distinguish between black, gray, and white, but theories of color vision are clearly of no help in explaining how they succeed. Human vision sidesteps the issue by constructing black and white in the brain. Bees have quite different and accessible mechanisms. As revealed by extensive tests of trained bees, bees learned two strong signals displayed on either target. The first input was the position and a measure of the green receptor modulation at the vertical edges of a black area, which included a measure of the angular width between the edges of black. They also learned the average position and total amount of blue reflected from white areas. These two inputs were sufficient to help decide which of two targets held the reward of sugar solution, but the bees cared nothing for the black or white as colors, or the direction of contrast at black/white edges. These findings provide a small step toward understanding, modeling, and implementing in silicon the anti-intuitive visual system of the honeybee, in feeding behavior. Keywords: vision, detectors, black/white, color, visual processing

  13. Stress, coping, and depression: testing a new hypothesis in a prospectively studied general population sample of U.S.-born Whites and Blacks.

    Science.gov (United States)

    Keyes, K M; Barnes, David M; Bates, L M

    2011-03-01

    The scarcity of empirically supported explanations for the Black/White prevalence difference in depression in the U.S. is a conspicuous gap in the literature. Recent evidence suggests that the paradoxical observation of decreased risk of depression but elevated rates of physical illness among Blacks in the U.S. compared with Whites may be accounted for by the use of coping behaviors (e.g., alcohol and nicotine consumption, overeating) among Blacks exposed to high stress levels. Such coping behaviors may mitigate deleterious effects of stressful exposures on mental health while increasing the risk of physical ailments. The racial patterning in mental and physical health outcomes could therefore be explained by this mechanism if a) these behaviors were more prevalent among Blacks than Whites and/or b) the effect of these behavioral responses to stress was differential by race. The present study challenges this hypothesis using longitudinal, nationally-representative data with comprehensive DSM-IV diagnoses. Data are drawn from 34,653 individuals sampled in Waves 1 (2001-2002) and 2 (2004-2005) as part of the US National Epidemiologic Survey on Alcohol and Related Conditions. Results showed that a) Blacks were less likely to engage in alcohol or nicotine consumption at low, moderate, and high levels of stress compared to Whites, and b) there was a significant three-way interaction between race, stress, and coping behavior for BMI only (F = 2.11, df = 12, p = 0.03), but, contrary to the hypothesis, elevated BMI was protective against depression in Blacks at low, not high, levels of stress. Further, engagement in unhealthy behaviors, especially at pathological levels, did not protect against depression in Blacks or in Whites. In sum, the impact of stress and coping processes on depression does not appear to operate differently in Blacks versus Whites. Further research testing innovative hypotheses that would explain the difference in Black/White depression prevalence is

  14. Color combination of conductive polymers for black electrochromism.

    Science.gov (United States)

    Shin, Haijin; Kim, Yuna; Bhuvana, Thiruvelu; Lee, Jiyea; Yang, Xu; Park, Cheolmin; Kim, Eunkyoung

    2012-01-01

    Conducting polymers that absorb three primary colors, red, green, and blue (RGB), were introduced with a yellow electrochromic polymer (Y) for the preparation of black electrochromic devices. Red poly(3-hexylthiophene) (P3HT) and blue poly(3,4-ethylenedioxythiophene) (PEDOT) were coated on one side of the electrode as a cathodically coloring electrochromic (EC) layer, while green poly(aniline-N-butylsulfonate) (PANBS) and yellow EC poly{[1,3-bis(9',9'-dihexylfluoren-20-yl)azulenyl]-alt-[2",7"-(9",9"-dihexylfluorenyl]} (PDHFA) were coated on the opposite electrode to complete a complementary EC device. The yellow PDHFA layer effectively compensated for absorption below 450 nm and above the 600 nm region, which was lacking in the RGB electrode. The resultant RGBY ECD provided a black color near the CIE black with L*, a*, and b* values of 32, -1.1, and 3.7, respectively, covering a broad absorption in the visible range in the colored state. The state of the black EC device was maintained, even after the electricity was turned off for 200 h, showing stable memory effect. © 2011 American Chemical Society

  15. Formation of black hole and emission of gravitational waves.

    Science.gov (United States)

    Nakamura, Takashi

    2006-12-01

    Numerical simulations were performed for the formation process of rotating black holes. It is suggested that Kerr black holes are formed for wide ranges of initial parameters. The nature of gravitational waves from a test particle falling into a Kerr black hole as well as the development of 3D numerical relativity for the coalescing binary neutron stars are discussed.

  16. Comparative studies of ginger ( Zingiber officinale ) and black pepper

    African Journals Online (AJOL)

    Extracts of two spices namely ginger (Zingiber officinale) and black pepper (Piper guinenses) were prepared in 0.4, 1.2, 2.4 and 3.6% concentrations. Soymilk and kunuzaki, were treated, respectively with the different concentrations and stored at ambient temperature for 5 days. The microbial load and identification were ...

  17. Black hole mass formula in the membrane paradigm

    Science.gov (United States)

    Lemos, José P. S.; Zaslavskii, Oleg B.

    2018-03-01

    The membrane paradigm approach adopts a timelike surface, stretched out off the null event horizon, to study several important black hole properties. We use this powerful tool to give a direct derivation of the black hole mass formula in the static and stationary cases without and with electric field. Since here the membrane is a self-gravitating material system, we go beyond the usual applicability on test particles and test fields of the paradigm.

  18. Trichinella surveillance in black bears (Ursus americanus) from Oregon, USA.

    Science.gov (United States)

    Mortenson, J A; Kent, M L; Fowler, D R; Chomel, B B; Immell, D A

    2014-01-01

    We used serology and muscle digestion to test black bears (Ursus americanus) from western Oregon, USA, for Trichinella. Results indicate black bears in Oregon are not part of a sylvatic cycle for Trichinella, and risk of human exposure to Trichinella larvae from eating black bear meat from Oregon appears low.

  19. Testing General Relativity with Stellar Orbits around the Supermassive Black Hole in Our Galactic Center.

    Science.gov (United States)

    Hees, A; Do, T; Ghez, A M; Martinez, G D; Naoz, S; Becklin, E E; Boehle, A; Chappell, S; Chu, D; Dehghanfar, A; Kosmo, K; Lu, J R; Matthews, K; Morris, M R; Sakai, S; Schödel, R; Witzel, G

    2017-05-26

    We demonstrate that short-period stars orbiting around the supermassive black hole in our Galactic center can successfully be used to probe the gravitational theory in a strong regime. We use 19 years of observations of the two best measured short-period stars orbiting our Galactic center to constrain a hypothetical fifth force that arises in various scenarios motivated by the development of a unification theory or in some models of dark matter and dark energy. No deviation from general relativity is reported and the fifth force strength is restricted to an upper 95% confidence limit of |α|<0.016 at a length scale of λ=150 astronomical units. We also derive a 95% confidence upper limit on a linear drift of the argument of periastron of the short-period star S0-2 of |ω[over ˙]_{S0-2}|<1.6×10^{-3}  rad/yr, which can be used to constrain various gravitational and astrophysical theories. This analysis provides the first fully self-consistent test of the gravitational theory using orbital dynamic in a strong gravitational regime, that of a supermassive black hole. A sensitivity analysis for future measurements is also presented.

  20. Black holes

    International Nuclear Information System (INIS)

    Feast, M.W.

    1981-01-01

    This article deals with two questions, namely whether it is possible for black holes to exist, and if the answer is yes, whether we have found any yet. In deciding whether black holes can exist or not the central role in the shaping of our universe played by the forse of gravity is discussed, and in deciding whether we are likely to find black holes in the universe the author looks at the way stars evolve, as well as white dwarfs and neutron stars. He also discusses the problem how to detect a black hole, possible black holes, a southern black hole, massive black holes, as well as why black holes are studied

  1. Post-Kerr black hole spectroscopy

    Science.gov (United States)

    Glampedakis, Kostas; Pappas, George; Silva, Hector O.; Berti, Emanuele

    2017-09-01

    One of the central goals of the newborn field of gravitational wave astronomy is to test gravity in the highly nonlinear, strong field regime characterizing the spacetime of black holes. In particular, "black hole spectroscopy" (the observation and identification of black hole quasinormal mode frequencies in the gravitational wave signal) is expected to become one of the main tools for probing the structure and dynamics of Kerr black holes. In this paper we take a significant step toward that goal by constructing a "post-Kerr" quasinormal mode formalism. The formalism incorporates a parametrized but general perturbative deviation from the Kerr metric and exploits the well-established connection between the properties of the spacetime's circular null geodesics and the fundamental quasinormal mode to provide approximate, eikonal limit formulas for the modes' complex frequencies. The resulting algebraic toolkit can be used in waveform templates for ringing black holes with the purpose of measuring deviations from the Kerr metric. As a first illustrative application of our framework, we consider the Johannsen-Psaltis deformed Kerr metric and compute the resulting deviation in the quasinormal mode frequency relative to the known Kerr result.

  2. Innermost stable circular orbit of spinning particle in charged spinning black hole background

    Science.gov (United States)

    Zhang, Yu-Peng; Wei, Shao-Wen; Guo, Wen-Di; Sui, Tao-Tao; Liu, Yu-Xiao

    2018-04-01

    In this paper we investigate the innermost stable circular orbit (ISCO) (spin-aligned or anti-aligned orbit) for a classical spinning test particle with the pole-dipole approximation in the background of Kerr-Newman black hole in the equatorial plane. It is shown that the orbit of the spinning particle is related to the spin of the test particle. The motion of the spinning test particle will be superluminal if its spin is too large. We give an additional condition by considering the superluminal constraint for the ISCO in the black hole backgrounds. We obtain numerically the relations between the ISCO and the properties of the black holes and the test particle. It is found that the radius of the ISCO for a spinning test particle is smaller than that of a nonspinning test particle in the black hole backgrounds.

  3. Preparation, thermal properties and thermal reliabilities of microencapsulated n-octadecane with acrylic-based polymer shells for thermal energy storage

    Energy Technology Data Exchange (ETDEWEB)

    Qiu, Xiaolin [Advanced Materials Institute and Clearer Production Key Laboratory, Graduate School at Shenzhen, Tsinghua University, Shenzhen 518055 (China); Key Laboratory of Advanced Materials, Department of Materials Science and Engineering, Tsinghua University, Haidian District, Beijing 100084 (China); Song, Guolin; Chu, Xiaodong; Li, Xuezhu [Advanced Materials Institute and Clearer Production Key Laboratory, Graduate School at Shenzhen, Tsinghua University, Shenzhen 518055 (China); Tang, Guoyi, E-mail: tanggy@tsinghua.edu.cn [Advanced Materials Institute and Clearer Production Key Laboratory, Graduate School at Shenzhen, Tsinghua University, Shenzhen 518055 (China); Key Laboratory of Advanced Materials, Department of Materials Science and Engineering, Tsinghua University, Haidian District, Beijing 100084 (China)

    2013-01-10

    Highlights: Black-Right-Pointing-Pointer n-Octadecane was encapsulated by p(butyl methacrylate) (PBMA) and p(butyl acrylate). Black-Right-Pointing-Pointer Microcapsules using divinylbenzene as crosslinking agent have better quality. Black-Right-Pointing-Pointer Microcapsule with butyl methacrylate-divinylbenzene has highest latent heat. Black-Right-Pointing-Pointer Microcapsule with butyl methacrylate-divinylbenzene has greatest thermal stability. Black-Right-Pointing-Pointer Phase change temperatures and enthalpies of the microcapsules varied little after thermal cycle. - Abstract: Microencapsulation of n-octadecane with crosslinked p(butyl methacrylate) (PBMA) and p(butyl acrylate) (PBA) as shells for thermal energy storage was carried out by a suspension-like polymerization. Divinylbenzene (DVB) and pentaerythritol triacrylate (PETA) were employed as crosslinking agents. The surface morphologies of the microencapsulated phase change materials (microPCMs) were studied by scanning electron microscopy (SEM). Thermal properties, thermal reliabilities and thermal stabilities of the as-prepared microPCMs were investigated by differential scanning calorimetry (DSC) and thermal gravimetric analysis (TGA). The microPCMs prepared by using DVB exhibit greater heat capacities and higher thermal stabilities compared with those prepared by using PETA. The thermal resistant temperature of the microPCM with BMA-DVB polymer was up to 248 Degree-Sign C. The phase change temperatures and latent heats of all the as-prepared microcapsules varied little after 1000 thermal cycles.

  4. Probing strong-field general relativity near black holes

    CERN Multimedia

    CERN. Geneva; Alvarez-Gaumé, Luís

    2005-01-01

    Nature has sprinkled black holes of various sizes throughout the universe, from stellar mass black holes in X-ray sources to supermassive black holes of billions of solar masses in quasars. Astronomers today are probing the spacetime near black holes using X-rays, and gravitational waves will open a different view in the near future. These tools give us an unprecedented opportunity to test ultra-strong-field general relativity, including the fundamental theorem of the uniqueness of the Kerr metric and Roger Penrose's cosmic censorship conjecture. Already, fascinating studies of spectral lines are showing the extreme gravitational lensing effects near black holes and allowing crude measurements of black hole spin. When the ESA-NASA gravitational wave detector LISA begins its observations in about 10 years, it will make measurements of dynamical spacetimes near black holes with an accuracy greater even than that which theoreticians can reach with their computations today. Most importantly, when gravitational wa...

  5. Black silicon with black bus-bar strings

    DEFF Research Database (Denmark)

    Davidsen, Rasmus Schmidt; Tang, Peter Torben; Mizushima, Io

    2016-01-01

    We present the combination of black silicon texturing and blackened bus-bar strings as a potential method for obtaining all-black solar panels, while using conventional, front-contacted solar cells. Black silicon was realized by mask-less reactive ion etching resulting in total, average reflectance...... below 0.5% across a 156x156 mm2 silicon wafer. Black bus-bars were realized by oxidized copper resulting in reflectance below 3% in the entire visible wavelength range. The combination of these two technologies may result in aesthetic, all-black panels based on conventional, front-contacted solar cells...

  6. The region interior to the event horizon of the regular Hayward black hole

    Science.gov (United States)

    Perez-Roman, Ivan; Bretón, Nora

    2018-06-01

    The Painlevé-Gullstrand coordinates allow us to explore the interior of the regular Hayward black hole. The behavior of an infalling particle in traversing the Hayward black hole is compared with the one inside the Schwarzschild and Reissner-Nordstrom singular black holes. When approaching the origin the test particle trajectories present differences depending if the center is regular or singular. The velocities of the infalling test particle into the modified Hayward black hole are analyzed as well. As compared with the normal Hayward, in the modified Hayward black hole the particle moves faster and the surface gravity is smaller.

  7. Black coal in Australia 1983-84: a statistical year book

    Energy Technology Data Exchange (ETDEWEB)

    1984-01-01

    An annual publication containing comprehensive statistical details of the Australian black coal industry. Included are statistics on coal supply and disposal, production, plant and equipment, coal preparation, manpower, exports, coal consumption, resources. Maps are included, also tables showing supply and disposal, production figures, employees, exports, consumption etc.

  8. Inside and outside stories of black-branes in anti de Sitter space

    International Nuclear Information System (INIS)

    Hansen, Jakob; Lee, Bum-Hoon; Park, Chanyong; Yeom, Dong-han

    2013-01-01

    In this paper, we investigate the dynamics inside and outside of black-branes in anti de Sitter space by numerical simulations using double-null formalism. We prepare a charged planar matter shell which, due to a negative cosmological constant, collapses and dynamically forms a black-brane with an apparent horizon, a singularity and a Cauchy horizon. The gravitational collapse cannot form a naked overcharged black-brane and hence weak cosmic censorship is safe. Although mass inflation occurs, the effect is much milder than in the case of charged black holes; hence, strong cosmic censorship seems not to be safe. We observed the scalar field dynamics outside the horizon. There should remain a non-trivial scalar field combination—‘charge cloud’—between the horizon and the boundary. This can give some meaning in terms of the AdS/CFT correspondence. (paper)

  9. Estimation of Theaflavins (TF) and Thearubigins (TR) Ratio in Black Tea Liquor Using Electronic Vision System

    Science.gov (United States)

    Akuli, Amitava; Pal, Abhra; Ghosh, Arunangshu; Bhattacharyya, Nabarun; Bandhopadhyya, Rajib; Tamuly, Pradip; Gogoi, Nagen

    2011-09-01

    Quality of black tea is generally assessed using organoleptic tests by professional tea tasters. They determine the quality of black tea based on its appearance (in dry condition and during liquor formation), aroma and taste. Variation in the above parameters is actually contributed by a number of chemical compounds like, Theaflavins (TF), Thearubigins (TR), Caffeine, Linalool, Geraniol etc. Among the above, TF and TR are the most important chemical compounds, which actually contribute to the formation of taste, colour and brightness in tea liquor. Estimation of TF and TR in black tea is generally done using a spectrophotometer instrument. But, the analysis technique undergoes a rigorous and time consuming effort for sample preparation; also the operation of costly spectrophotometer requires expert manpower. To overcome above problems an Electronic Vision System based on digital image processing technique has been developed. The system is faster, low cost, repeatable and can estimate the amount of TF and TR ratio for black tea liquor with accuracy. The data analysis is done using Principal Component Analysis (PCA), Multiple Linear Regression (MLR) and Multiple Discriminate Analysis (MDA). A correlation has been established between colour of tea liquor images and TF, TR ratio. This paper describes the newly developed E-Vision system, experimental methods, data analysis algorithms and finally, the performance of the E-Vision System as compared to the results of traditional spectrophotometer.

  10. Problems with tunneling of thin shells from black holes

    Indian Academy of Sciences (India)

    is proposed. However, it is shown that this gives half the correct temperature for black ... Hawking radiation was calculated for the emission of test particles. (not affecting ... needed to get an expression for tunneling in black hole backgrounds.

  11. Weaponization and Prisonization of Toronto’s Black Male Youth

    Directory of Open Access Journals (Sweden)

    Wesley Crichlow

    2014-12-01

    Full Text Available Informed by Galtung (1969, Anderson (2012 and Wacquant (2001, this paper argues that a lifetime of spiralling and everyday state structural violence and overtly racist criminal profiling principally targeted at young Black men living in the Toronto Community Housing Corporation prepares them for prison. Moreover, it contends that interpersonal violence, transmitted from generation to generation and producing a vicious cycle, is a manifestation of institutionalized and systemic inequity. In the context of a hypermasculine culture, young Black men are both victims and participants in a dialectic of interpersonal-structural violence. Routinely precipitated by powerful state actors and agencies of criminal justice, public policy and assorted ‘moral entrepreneurs’, young Black men have their masculinity weaponized and prisonized by the state’s low-intensity declaration of war against them, and, among others, the poor, LGBTQ, immigrants, and First Nations and other people of colour.

  12. Scattering of particles by deformed non-rotating black holes

    International Nuclear Information System (INIS)

    Pei, Guancheng; Bambi, Cosimo

    2015-01-01

    We study the excitation of axial quasi-normal modes of deformed non-rotating black holes by test particles and we compare the associated gravitational wave signal with that expected in general relativity from a Schwarzschild black hole. Deviations from standard predictions are quantified by an effective deformation parameter, which takes into account deviations from both the Schwarzschild metric and the Einstein equations. We show that, at least in the case of non-rotating black holes, it is possible to test the metric around the compact object, in the sense that the measurement of the gravitational wave spectrum can constrain possible deviations from the Schwarzschild solution. (orig.)

  13. 40 CFR 1045.305 - How must I prepare and test my production-line engines?

    Science.gov (United States)

    2010-07-01

    ... production-line engines? 1045.305 Section 1045.305 Protection of Environment ENVIRONMENTAL PROTECTION AGENCY (CONTINUED) AIR POLLUTION CONTROLS CONTROL OF EMISSIONS FROM SPARK-IGNITION PROPULSION MARINE ENGINES AND VESSELS Testing Production-line Engines § 1045.305 How must I prepare and test my production-line engines...

  14. 40 CFR 1048.305 - How must I prepare and test my production-line engines?

    Science.gov (United States)

    2010-07-01

    ... production-line engines? 1048.305 Section 1048.305 Protection of Environment ENVIRONMENTAL PROTECTION AGENCY (CONTINUED) AIR POLLUTION CONTROLS CONTROL OF EMISSIONS FROM NEW, LARGE NONROAD SPARK-IGNITION ENGINES Testing Production-line Engines § 1048.305 How must I prepare and test my production-line engines? This...

  15. Black rings

    International Nuclear Information System (INIS)

    Emparan, Roberto; Reall, Harvey S

    2006-01-01

    A black ring is a five-dimensional black hole with an event horizon of topology S 1 x S 2 . We provide an introduction to the description of black rings in general relativity and string theory. Novel aspects of the presentation include a new approach to constructing black ring coordinates and a critical review of black ring microscopics. (topical review)

  16. Bumpy black holes from spontaneous Lorentz violation

    International Nuclear Information System (INIS)

    Dubovsky, Sergei; Tinyakov, Peter; Zaldarriaga, Matias

    2007-01-01

    We consider black holes in Lorentz violating theories of massive gravity. We argue that in these theories black hole solutions are no longer universal and exhibit a large number of hairs. If they exist, these hairs probe the singularity inside the black hole providing a window into quantum gravity. The existence of these hairs can be tested by future gravitational wave observatories. We generically expect that the effects we discuss will be larger for the more massive black holes. In the simplest models the strength of the hairs is controlled by the same parameter that sets the mass of the graviton (tensor modes). Then the upper limit on this mass coming from the inferred gravitational radiation emitted by binary pulsars implies that hairs are likely to be suppressed for almost the entire mass range of the super-massive black holes in the centers of galaxies

  17. Chinese Students' Perceptions of the Value of Test Preparation Courses for the TOEFL iBT: Merit, Worth, and Significance

    Science.gov (United States)

    Ma, Jia; Cheng, Liying

    2015-01-01

    Test preparation for high-stakes English language tests has received increasing research attention in the language assessment field; however, little is known about what aspects of test preparation students attend to and value. In this study, we considered the perspectives of 12 Chinese students who were enrolled in various academic programs in a…

  18. Selection and Characterization of Carbon Black and Surfactants for Development of Small Scale Uranium Oxicarbide Kernels

    Energy Technology Data Exchange (ETDEWEB)

    Contescu, Cristian I [ORNL

    2006-01-01

    This report supports the effort for development of small scale fabrication of UCO (a mixture of UO{sub 2} and UC{sub 2}) fuel kernels for the generation IV high temperature gas reactor program. In particular, it is focused on optimization of dispersion conditions of carbon black in the broths from which carbon-containing (UO{sub 2} {center_dot} H{sub 2}O + C) gel spheres are prepared by internal gelation. The broth results from mixing a hexamethylenetetramine (HMTA) and urea solution with an acid-deficient uranyl nitrate (ADUN) solution. Carbon black, which is previously added to one or other of the components, must stay dispersed during gelation. The report provides a detailed description of characterization efforts and results, aimed at identification and testing carbon black and surfactant combinations that would produce stable dispersions, with carbon particle sizes below 1 {micro}m, in aqueous HMTA/urea and ADUN solutions. A battery of characterization methods was used to identify the properties affecting the water dispersability of carbon blacks, such as surface area, aggregate morphology, volatile content, and, most importantly, surface chemistry. The report introduces the basic principles for each physical or chemical method of carbon black characterization, lists the results obtained, and underlines cross-correlations between methods. Particular attention is given to a newly developed method for characterization of surface chemical groups on carbons in terms of their acid-base properties (pK{sub a} spectra) based on potentiometric titration. Fourier-transform infrared (FTIR) spectroscopy was used to confirm the identity of surfactants, both ionic and non-ionic. In addition, background information on carbon black properties and the mechanism by which surfactants disperse carbon black in water is also provided. A list of main physical and chemical properties characterized, samples analyzed, and results obtained, as well as information on the desired trend or

  19. "Black Like Me": Reframing Blackness for Decolonial Politics

    Science.gov (United States)

    Dei, George J. Sefa

    2018-01-01

    From a particular vantage point, as an African-born scholar with a politics to affirm my Black subjectivity and Indigeneity in a diasporic context, my article engages a (re)theorization of Blackness for decolonial politics. Building on existing works of how Black scholars, themselves, have theorized Blackness, and recognizing the fluid,…

  20. Thermodynamic phase transition in the rainbow Schwarzschild black hole

    International Nuclear Information System (INIS)

    Gim, Yongwan; Kim, Wontae

    2014-01-01

    We study the thermodynamic phase transition in the rainbow Schwarzschild black hole where the metric depends on the energy of the test particle. Identifying the black hole temperature with the energy from the modified dispersion relation, we obtain the modified entropy and thermodynamic energy along with the modified local temperature in the cavity to provide well defined black hole states. It is found that apart from the conventional critical temperature related to Hawking-Page phase transition there appears an additional critical temperature which is of relevance to the existence of a locally stable tiny black hole; however, the off-shell free energy tells us that this black hole should eventually tunnel into the stable large black hole. Finally, we discuss the reason why the temperature near the horizon is finite in the rainbow black hole by employing the running gravitational coupling constant, whereas it is divergent near the horizon in the ordinary Schwarzschild black hole

  1. LOW-MASS AGNs AND THEIR RELATION TO THE FUNDAMENTAL PLANE OF BLACK HOLE ACCRETION

    Energy Technology Data Exchange (ETDEWEB)

    Gültekin, Kayhan; King, Ashley L.; Miller, Jon M. [Department of Astronomy, University of Michigan, 500 Church Street, Ann Arbor, MI 48109 (United States); Cackett, Edward M. [Department of Physics and Astronomy, Wayne State University, 666 West Hancock Street, Detroit, MI 48201 (United States); Pinkney, Jason, E-mail: kayhan@umich.edu [Department of Physics and Astronomy, Ohio Northern University, 525 S. Main St., Ada, OH 45810 (United States)

    2014-06-20

    We put active galactic nuclei (AGNs) with low-mass black holes on the fundamental plane of black hole accretion—the plane that relates X-ray emission, radio emission, and mass of an accreting black hole—to test whether or not the relation is universal for both stellar-mass and supermassive black holes. We use new Chandra X-ray and Very Large Array radio observations of a sample of black holes with masses less than 10{sup 6.3} M {sub ☉}, which have the best leverage for determining whether supermassive black holes and stellar-mass black holes belong on the same plane. Our results suggest that the two different classes of black holes both belong on the same relation. These results allow us to conclude that the fundamental plane is suitable for use in estimating supermassive black hole masses smaller than ∼10{sup 7} M {sub ☉}, in testing for intermediate-mass black holes, and in estimating masses at high accretion rates.

  2. Media-fill simulation tests in manual and robotic aseptic preparation of injection solutions in syringes.

    Science.gov (United States)

    Krämer, Irene; Federici, Matteo; Kaiser, Vanessa; Thiesen, Judith

    2016-04-01

    The purpose of this study was to evaluate the contamination rate of media-fill products either prepared automated with a robotic system (APOTECAchemo™) or prepared manually at cytotoxic workbenches in the same cleanroom environment and by experienced operators. Media fills were completed by microbiological environmental control in the critical zones and used to validate the cleaning and disinfection procedures of the robotic system. The aseptic preparation of patient individual ready-to-use injection solutions was simulated by using double concentrated tryptic soy broth as growth medium, water for injection and plastic syringes as primary packaging materials. Media fills were either prepared automated (500 units) in the robot or manually (500 units) in cytotoxic workbenches in the same cleanroom over a period of 18 working days. The test solutions were incubated at room temperature (22℃) over 4 weeks. Products were visually inspected for turbidity after a 2-week and 4-week period. Following incubation, growth promotion tests were performed with Staphylococcus epidermidis. During the media-fill procedures, passive air monitoring was performed with settle plates and surface monitoring with contact plates on predefined locations as well as fingerprints. The plates got incubated for 5-7 days at room temperature, followed by 2-3 days at 30-35℃ and the colony forming units (cfu) counted after both periods. The robot was cleaned and disinfected according to the established standard operating procedure on two working days prior to the media-fill session, while on six other working days only six critical components were sanitized at the end of the media-fill sessions. Every day UV irradiation was operated for 4 h after finishing work. None of the 1000 media-fill products prepared in the two different settings showed turbidity after the incubation period thereby indicating no contamination with microorganisms. All products remained uniform, clear, and light

  3. Identification and Prioritization of “Black Spots” without Using Accident Information

    Directory of Open Access Journals (Sweden)

    Mahmoudreza Keymanesh

    2017-01-01

    Full Text Available It is attempted to identify and prioritize the accident prone points (black spots in “Iraanshahr-Sarbaaz-Chabahar” road located in Baluchistan, Iran, without no use of accident data but rather using Analytic Hierarchy Process (AHP, which is the enhanced procedure of road safety audit technique. First, by surveying the whole route, all factors that could influence accidents in this road were specified; then the route was divided into eight sections; this division was performed based on the uniformity and homogeny of each section in terms of geometric design and regional conditions. In each section, potentially hazardous locations were identified and some questionnaires were prepared, which were filled by 5 road traffic experts familiar with the route; then the collected data were analyzed by Analytical Hierarchy Process (AHP using Expert Choice Software and the black spots were identified and prioritized. Finally, these black spots were compared with the black spots that had been obtained by traffic police based on accident data.

  4. Gammaherpesvirus carrier status of black wildebeest (Connochaetes gnou in South Africa

    Directory of Open Access Journals (Sweden)

    J.A. Pretorius

    2008-05-01

    Full Text Available Malignant catarrhal fever (MCF is an economically important disease primarily of domestic cattle with a high case fatality rate. It is caused by either alcelaphine herpesvirus type 1 (AlHV-1 or ovine herpesvirus type 2 (OvHV-2. The major reservoir host of AlHV-1 is the blue wildebeest (Connochaetes taurinus, but it is generally accepted that the black wildebeest (Connochaetes gnou is also a reservoir host. No viral studies in the black wildebeest have been reported and the carrier status of black wildebeest has not been documented. Specimens were collected from several game farms and conservation areas in central South Africa representing the geographical area historically linked to the natural habitat of the black wildebeest. Specimens were obtained from 304 black wildebeest of different ages and sex, as well as 51 black wildebeest foetuses at different stages of gestation. Virus was isolated from a black wildebeest calf. Morphological features and antigenic characteristics suggested it to be a gammaherpesvirus closely related to AlHV-1. All serum samples tested positive with a competitive inhibition enzyme-linked immunosorbent assay (CI-ELISA for group-specific malignant catarrhal fever virus antibody. ASYBR Green real-time PCR assay was developed for the detection of gammaherpesviral DNA. Only 15.8 % of the animals tested positive with the real-time PCR assay whereas 90 % of the foetuses tested positive. This finding suggests that, unlike OvHV-2 infection in lambs in which the infection takes place after weaning, the virus in black wildebeest is mainly transmitted in utero or soon after birth. The results suggest that black wildebeest are latent carriers of a gammaherpesvirus similar or closely related to AlHV-1 present in blue wildebeest and that it is likely that all black wildebeest are persistently infected.

  5. Characterization of Pd catalyst-electrodes deposited on YSZ: Influence of the preparation technique and the presence of a ceria interlayer

    Energy Technology Data Exchange (ETDEWEB)

    Jimenez-Borja, Carmen, E-mail: Carmen.JBorja@uclm.es [Departamento de Ingenieria Quimica, Facultad de Ciencias Quimicas, Universidad de Castilla-La Mancha. Avenida Camilo Jose Cela 12, 13071 Ciudad Real (Spain); Matei, Florina [Department of Petroleum Processing Engineering and Environmental Protection, Petroleum - Gas University of Ploiesti (Romania); Dorado, Fernando; Valverde, Jose Luis [Departamento de Ingenieria Quimica, Facultad de Ciencias Quimicas, Universidad de Castilla-La Mancha. Avenida Camilo Jose Cela 12, 13071 Ciudad Real (Spain)

    2012-11-15

    Highlights: Black-Right-Pointing-Pointer Impregnation of palladium over YSZ led to more dispersed films. Black-Right-Pointing-Pointer XPS spectra indicated electron deficient Pd{sup 2+} species on the surface of palladium films. Black-Right-Pointing-Pointer Impregnated palladium films were more active than those prepared by paste deposition Black-Right-Pointing-Pointer The addition of a CeO{sub 2} interlayer enhanced the catalytic rate for the impregnated samples. - Abstract: Palladium catalyst-electrodes supported on Y{sub 2}O{sub 3}-stabilized-ZrO{sub 2} (YSZ) prepared either by paste deposition or wet impregnation technique were characterized using X-ray photoelectron spectroscopy (XPS), X-ray diffraction (XRD), scanning electron microscopy (SEM) and transmission electron microscopy (TEM). It was found a strong dependence of the catalytic film preparation technique as well as of the presence of a ceria interlayer between the palladium film and the solid electrolyte on the catalytic activity towards methane oxidation. Impregnated palladium films were found to be more active than films prepared by paste deposition. Besides, the addition of ceria allowed stabilizing the palladium active phase for methane oxidation.

  6. An explicit harmonic code for black-hole evolution using excision

    International Nuclear Information System (INIS)

    Szilagyi, Bela; Pollney, Denis; Rezzolla, Luciano; Thornburg, Jonathan; Winicour, Jeffrey

    2007-01-01

    We describe an explicit in time, finite-difference code designed to simulate black holes by using the excision method. The code is based upon the harmonic formulation of the Einstein equations and incorporates several features regarding the well-posedness and numerical stability of the initial-boundary problem for the quasilinear wave equation. After a discussion of the equations solved and of the techniques employed, we present a series of testbeds carried out to validate the code. Such tests range from the evolution of isolated black holes to the head-on collision of two black holes and then to a binary black hole inspiral and merger. Besides assessing the accuracy of the code, the inspiral and merger test has revealed that the marginally trapped surfaces contained within the common apparent horizon of the merged black hole can touch and even intersect. This novel feature in the dynamics of the marginally trapped surfaces is unexpected but consistent with theorems on the properties of these surfaces

  7. An explicit harmonic code for black-hole evolution using excision

    Energy Technology Data Exchange (ETDEWEB)

    Szilagyi, Bela [Max-Planck-Institut fuer Gravitationsphysik, Albert-Einstein-Institut, Golm (Germany); Pollney, Denis [Max-Planck-Institut fuer Gravitationsphysik, Albert-Einstein-Institut, Golm (Germany); Rezzolla, Luciano [Max-Planck-Institut fuer Gravitationsphysik, Albert-Einstein-Institut, Golm (Germany); Thornburg, Jonathan [Max-Planck-Institut fuer Gravitationsphysik, Albert-Einstein-Institut, Golm (Germany); Winicour, Jeffrey [Max-Planck-Institut fuer Gravitationsphysik, Albert-Einstein-Institut, Golm (Germany)

    2007-06-21

    We describe an explicit in time, finite-difference code designed to simulate black holes by using the excision method. The code is based upon the harmonic formulation of the Einstein equations and incorporates several features regarding the well-posedness and numerical stability of the initial-boundary problem for the quasilinear wave equation. After a discussion of the equations solved and of the techniques employed, we present a series of testbeds carried out to validate the code. Such tests range from the evolution of isolated black holes to the head-on collision of two black holes and then to a binary black hole inspiral and merger. Besides assessing the accuracy of the code, the inspiral and merger test has revealed that the marginally trapped surfaces contained within the common apparent horizon of the merged black hole can touch and even intersect. This novel feature in the dynamics of the marginally trapped surfaces is unexpected but consistent with theorems on the properties of these surfaces.

  8. HIV Testing Practices and Interest in Self-Testing Options among Young, Black Men Who Have Sex with Men in North Carolina

    Science.gov (United States)

    HURT, Christopher B.; SONI, Karina; MILLER, William C.; HIGHTOW-WEIDMAN, Lisa B.

    2016-01-01

    Background Young, Black men who have sex with men (YBMSM) experience disproportionately high HIV incidence in the United States. Relative to other at-risk populations, less is known about their HIV testing behaviors and preferences regarding self-testing. Methods We used an online survey to investigate testing practices and interest in self-testing among HIV-uninfected, 18–30 year-old YBMSM in North Carolina. Results From July 2014 – March 2015, 212 completed the survey; median age was 24 years. Among 175 (83%) who had ever been tested, 160 (91%) reported testing in the prior year, 124 (71%) tested at least every 6 months, and 71 (40%) tested at least quarterly. About three-quarters (77%; n=164) were aware of HIV self-testing; 35 (17%) had ever purchased rapid (n=27) or dried blood spot-based (n=14) kits. Participants aware of kits had greater intention to test in the next 6 months; were more likely to have income for basic necessities and to ask sex partners about HIV status; and were less likely to have a main sex partner or to have had transactional sex. Among 142 participants at least somewhat likely to self-test in the future, convenience (35%), privacy (23%), and rapid result delivery (18%) were the principal motivators. Conclusions Eight of every ten YBMSM have ever been tested for HIV, but inter-test intervals remain unacceptably long for many. Awareness of and interest in self-testing is substantial, but few have used this method. Expanded use of self-tests could help increase the frequency of HIV testing in this epidemiologically important population. PMID:27513387

  9. Academic and Career Advancement for Black Male Athletes at NCAA Division I Institutions

    Science.gov (United States)

    Baker, Ashley R.; Hawkins, Billy J.

    2016-01-01

    This chapter examines the structural arrangements and challenges many Black male athletes encounter as a result of their use of sport for upward social mobility. Recommendations to enhance their preparation and advancement are provided.

  10. Retail Socialization: The Preparation of Black High School Students for Employment in Business

    Science.gov (United States)

    Collins, Thomas W.; And Others

    1978-01-01

    This study of a Distributive Education Program in a predominantly black southern urban high school notes that the graduates of the vocational program enter jobs which ultimately may not be able to provide them with stable employment and job security and that these students would not pose much of a threat to their white classmates in competition…

  11. Enhanced photoelectrochemical properties of copper-assisted catalyzed etching black silicon by electrodepositing cobalt

    Science.gov (United States)

    Cai, Weidong; Xiong, Haiying; Su, Xiaodong; Zhou, Hao; Shen, Mingrong; Fang, Liang

    2017-11-01

    Black silicon (Si) photoelectrodes are promising for improving the performance of photoelectrochemical (PEC) water splitting. Here, we report the fabrication of p-black Si and n+p-black Si photocathodes via a controllable copper-assisted catalyzed etching method. The etching process affects only the topmost less than 200 nm of Si and is independent of the surface doping. The synergistic effects of the excellent light harvesting of the black Si and the improved charge transfer properties of the p-n junction boost the production and utilization of photogenerated carriers. The mean reflectance of the pristine Si samples is about 10% from 400 to 950 nm, while that of the black Si samples is reduced as low as 5%. In addition, the PEC properties of the n+p-black Si photocathode can be further enhanced by depositing a cobalt (Co) layer. Compared with the p-Si sample, the onset potential of the Co/n+p-black Si photocathode is positively shifted by 560 mV to 0.33 V vs. reversible hydrogen electrode and the saturation photocurrent density is increased from 22.7 to 32.6 mA/cm2. The design of the Co/n+p-black Si photocathode offers an efficient strategy for preparing PEC solar energy conversion devices.

  12. Unexpected attraction of polarotactic water-leaving insects to matt black car surfaces: mattness of paintwork cannot eliminate the polarized light pollution of black cars.

    Directory of Open Access Journals (Sweden)

    Miklos Blaho

    Full Text Available The horizontally polarizing surface parts of shiny black cars (the reflection-polarization characteristics of which are similar to those of water surfaces attract water-leaving polarotactic insects. Thus, shiny black cars are typical sources of polarized light pollution endangering water-leaving insects. A new fashion fad is to make car-bodies matt black or grey. Since rough (matt surfaces depolarize the reflected light, one of the ways of reducing polarized light pollution is to make matt the concerned surface. Consequently, matt black/grey cars may not induce polarized light pollution, which would be an advantageous feature for environmental protection. To test this idea, we performed field experiments with horizontal shiny and matt black car-body surfaces laid on the ground. Using imaging polarimetry, in multiple-choice field experiments we investigated the attractiveness of these test surfaces to various water-leaving polarotactic insects and obtained the following results: (i The attractiveness of black car-bodies to polarotactic insects depends in complex manner on the surface roughness (shiny, matt and species (mayflies, dolichopodids, tabanids. (ii Non-expectedly, the matt dark grey car finish is much more attractive to mayflies (being endangered and protected in many countries than matt black finish. (iii The polarized light pollution of shiny black cars usually cannot be reduced with the use of matt painting. On the basis of these, our two novel findings are that (a matt car-paints are highly polarization reflecting, and (b these matt paints are not suitable to repel polarotactic insects. Hence, the recent technology used to make matt the car-bodies cannot eliminate or even can enhance the attractiveness of black/grey cars to water-leaving insects. Thus, changing shiny black car painting to matt one is a disadvantageous fashion fad concerning the reduction of polarized light pollution of black vehicles.

  13. Unexpected attraction of polarotactic water-leaving insects to matt black car surfaces: mattness of paintwork cannot eliminate the polarized light pollution of black cars.

    Science.gov (United States)

    Blaho, Miklos; Herczeg, Tamas; Kriska, Gyorgy; Egri, Adam; Szaz, Denes; Farkas, Alexandra; Tarjanyi, Nikolett; Czinke, Laszlo; Barta, Andras; Horvath, Gabor

    2014-01-01

    The horizontally polarizing surface parts of shiny black cars (the reflection-polarization characteristics of which are similar to those of water surfaces) attract water-leaving polarotactic insects. Thus, shiny black cars are typical sources of polarized light pollution endangering water-leaving insects. A new fashion fad is to make car-bodies matt black or grey. Since rough (matt) surfaces depolarize the reflected light, one of the ways of reducing polarized light pollution is to make matt the concerned surface. Consequently, matt black/grey cars may not induce polarized light pollution, which would be an advantageous feature for environmental protection. To test this idea, we performed field experiments with horizontal shiny and matt black car-body surfaces laid on the ground. Using imaging polarimetry, in multiple-choice field experiments we investigated the attractiveness of these test surfaces to various water-leaving polarotactic insects and obtained the following results: (i) The attractiveness of black car-bodies to polarotactic insects depends in complex manner on the surface roughness (shiny, matt) and species (mayflies, dolichopodids, tabanids). (ii) Non-expectedly, the matt dark grey car finish is much more attractive to mayflies (being endangered and protected in many countries) than matt black finish. (iii) The polarized light pollution of shiny black cars usually cannot be reduced with the use of matt painting. On the basis of these, our two novel findings are that (a) matt car-paints are highly polarization reflecting, and (b) these matt paints are not suitable to repel polarotactic insects. Hence, the recent technology used to make matt the car-bodies cannot eliminate or even can enhance the attractiveness of black/grey cars to water-leaving insects. Thus, changing shiny black car painting to matt one is a disadvantageous fashion fad concerning the reduction of polarized light pollution of black vehicles.

  14. The effects of commercial preparations of herbal supplements commonly used by women on the biotransformation of fluorogenic substrates by human cytochromes P450.

    Science.gov (United States)

    Ho, Shirley H Y; Singh, Mohini; Holloway, Alison C; Crankshaw, Denis J

    2011-07-01

    The study set out to determine the potential for commercially available preparations of black cohosh (Actaea racemosa), chaste tree berry (Vitex agnus-castus), crampbark (Viburnum opulus) and false unicorn (Chamaelirium luteum) to inhibit the major human drug metabolizing enzymes CYP1A2, CYP2C9, CYP2C19, CYP2D6 and CYP3A4 as well as CYP1A1 which activates some carcinogens. In vitro microplate-based assays using cDNA-expressed CYP450 isoforms and fluorogenic substrates were used. Components of the commercial herbal preparations interfered with the assays and limited the concentration ranges that could be tested. Nevertheless, the fluorogenic assays were robust, reproducible and easy to perform and thus are still useful for initial screening for potential herb-drug interactions. None of the preparations affected CYPs 1A1 or 2C9 at the concentrations tested but all preparations inhibited some of the enzymes with potencies around 1 μg/mL. The three most potent interactions were: chaste tree berry and CYP2C19 (IC₅₀) 0.22 μg/mL); chaste tree berry and CYP3A4 (IC₅₀) 0.3 μg/mL); black cohosh and CYP2C19 (IC₅₀) 0.37 μg/mL,). Thus, the study successfully identified the potential for the commercial herbal preparations to inhibit human drug metabolizing enzymes. Whether this potential translates into clinically significant herb-drug interactions can only be confirmed by appropriate in vivo studies. Copyright © 2011 John Wiley & Sons, Ltd.

  15. Black Alcoholism.

    Science.gov (United States)

    Watts, Thomas D.; Wright, Roosevelt

    1988-01-01

    Examines some aspects of the problem of alcoholism among Blacks, asserting that Black alcoholism can best be considered in an ecological, environmental, sociocultural, and public health context. Notes need for further research on alcoholism among Blacks and for action to reduce the problem of Black alcoholism. (NB)

  16. Black holes in the presence of dark energy

    International Nuclear Information System (INIS)

    Babichev, E O; Dokuchaev, V I; Eroshenko, Yu N

    2013-01-01

    The new, rapidly developing field of theoretical research—studies of dark energy interacting with black holes (and, in particular, accreting onto black holes)–—is reviewed. The term 'dark energy' is meant to cover a wide range of field theory models, as well as perfect fluids with various equations of state, including cosmological dark energy. Various accretion models are analyzed in terms of the simplest test field approximation or by allowing back reaction on the black-hole metric. The behavior of various types of dark energy in the vicinity of Schwarzschild and electrically charged black holes is examined. Nontrivial effects due to the presence of dark energy in the black hole vicinity are discussed. In particular, a physical explanation is given of why the black hole mass decreases when phantom energy is being accreted, a process in which the basic energy conditions of the famous theorem of nondecreasing horizon area in classical black holes are violated. The theoretical possibility of a signal escaping from beneath the black hole event horizon is discussed for a number of dark energy models. Finally, the violation of the laws of thermodynamics by black holes in the presence of noncanonical fields is considered. (reviews of topical problems)

  17. Surface nucleation and independent growth of Ce(OH)4 within confinement space on modified carbon black surface to prepare nano-CeO2 without agglomeration

    Science.gov (United States)

    Zhang, Xinyue; Xia, Chunhui; Li, Kaitao; Lin, Yanjun

    2018-04-01

    Highly dispersed negative carboxyl groups can be formed on carbon black (CB) surface modified with strong nitric acid. Therefore positive cations can be uniformly absorbed by carboxyl groups and precipitated within a confinement space on modified CB surface to prepare highly dispersed nanomaterials. In this paper, the formation and dispersion status of surface negative carboxyl groups, adsorption status of Ce3+, surface confinement nucleation, crystallization and calcination process were studied by EDS, SEM, and laser particle size analysis. The results show that the carboxyl groups formed on modified CB surface are highly dispersed, and Ce3+ cations can be uniformly anchored by carboxyl groups. Therefore, highly dispersed Ce3+ can react with OH- within a confinement surface region to form positive nano-Ce(OH)4 nuclei which also can be adsorbed by electrostatic attraction. After independent growth of Ce(OH)4 without agglomeration, highly dispersed CeO2 nanoparticles without agglomeration can be prepared together with the help of effectively isolates by CO2 released in the combustion of CB.

  18. Method for preparation of uranium hydride

    International Nuclear Information System (INIS)

    Gorski, M.S.; Goncalves, Miriam; Mirage, A.; Lima, W. de.

    1985-01-01

    A method for preparation of Uranium Hydride starting from Hidrogen and Uranium is described. In the temperature range of 250 0 up to 350 0 C, and pressures above 10torr, Hydrogen reacts smoothly with Uranium turnings forming a fine black or dark gray powder (UH 3 ). Samples containing a significant amount of oxides show a delay before the reaction begging. (Author) [pt

  19. Nuclear nonsense, black-market bombs, and fissile flim-flam

    International Nuclear Information System (INIS)

    Belyaninov, K.

    1994-01-01

    This article describes the findings of three undercover Russian journalists who broke into the black market for nuclear materials. They relate their experiences of contacting brokers, describe the proposed deals, and reveal the results of some of the tests of samples. The economic pressures behind the black market are described. The dangers to the participants of the black market and potential dangers to the public from uncontrolled trade in nuclear materials are discussed

  20. Concerning production and decay of mini black holes

    CERN Document Server

    Hajdukovic, D

    2007-01-01

    In the next few years, theories predicting possibility to create mini black holes will be tested at CERN. Either experimental verification or rejection of these theories is of great scientific importance. There is a large consensus that, if successfully created, these short living mini black holes will decay through thermal (Hawking's) radiation. In the present comment we point out, that under assumption of the gravitational repulsion between matter and antimatter (in short we call it antigravity), thermal radiation may be dominated by a non-thermal radiation (being the consequence of pair creation from the vacuum, by gravitational field, which in the case of antigravity, pushes particles and antiparticles in opposite directions). Thus, the eventual creation of mini black holes may turn to be an unexpected opportunity to test the existence of antigravity.

  1. The Preparation of the Cryomagnets and the Assembly of the LHC Test String 2

    CERN Document Server

    Andujar, O; Calzas-Rodriguez, C; Cruikshank, P; Desebe, O; Dobers, T; Jacquemod, A; Kos, N; Lepeule, P; Maan, W; Missiaen, D; Parma, Vittorio; Riddone, G; Rodríguez-Mateos, F; Rohmig, P; Saban, R I; Schneider, G; Serio, L; Skoczen, Blazej; Tock, J P; Veness, R J M; Vuitton, C

    2001-01-01

    The numerous complex activities required to prepare the cryomagnets for the installation in String 2 are described. These include the configuration of the mechanical interfaces, thee conditioning of the beam tubes, the installation of beam screens and the instrumentation as well as the final checks. The preparation of the cryomagnets for String 2 has been a dress rehearsal for the preparation that the cryomagnets will undergo before their installation in the tunnel. After a description of the interconnection procedures of the components for String 2, the tests carried-out to release the String for operation are described. A brief account of the lessons learnt is also given.

  2. Some astrophysical processes around magnetized black hole

    Science.gov (United States)

    Kološ, M.; Tursunov, A.; Stuchlík, Z.

    2018-01-01

    We study the dynamics of charged test particles in the vicinity of a black hole immersed into an asymptotically uniform external magnetic field. A real magnetic field around a black hole will be far away from to be completely regular and uniform, a uniform magnetic field is used as linear approximation. Ionized particle acceleration, charged particle oscillations and synchrotron radiation of moving charged particle have been studied.

  3. CHAOTIC MOTION OF CHARGED PARTICLES IN AN ELECTROMAGNETIC FIELD SURROUNDING A ROTATING BLACK HOLE

    International Nuclear Information System (INIS)

    Takahashi, Masaaki; Koyama, Hiroko

    2009-01-01

    The observational data from some black hole candidates suggest the importance of electromagnetic fields in the vicinity of a black hole. Highly magnetized disk accretion may play an importance rule, and large-scale magnetic field may be formed above the disk surface. Then, we expect that the nature of the black hole spacetime would be revealed by magnetic phenomena near the black hole. We will start investigating the motion of a charged test particle which depends on the initial parameter setting in the black hole dipole magnetic field, which is a test field on the Kerr spacetime. Particularly, we study the spin effects of a rotating black hole on the motion of the charged test particle trapped in magnetic field lines. We make detailed analysis for the particle's trajectories by using the Poincare map method, and show the chaotic properties that depend on the black hole spin. We find that the dragging effects of the spacetime by a rotating black hole weaken the chaotic properties and generate regular trajectories for some sets of initial parameters, while the chaotic properties dominate on the trajectories for slowly rotating black hole cases. The dragging effects can generate the fourth adiabatic invariant on the particle motion approximately.

  4. The use of bacteriological preparates to test processes in radiation sterilization

    International Nuclear Information System (INIS)

    Gazso, L.; Igali, S.; Kovacs, A.

    1976-01-01

    Environmental factors influencing the irradiation sensitivity of micro-organisms, bacterium stocks being suitable for biological checking up and spore test organism used nowadays are reviewed. According to the tests made on Bacillus pumilus E601 and Bacillus sphaericus Csub(I)A stockes with Noratom, PX-γ-30 and 60 Co radiation sources the irradiation sensitivity of the same products irradiated with the same dose can differ in the function of the radiation source and the dose rate. It seems necessary to produce the test preparates in the same way in a central laboratory and to calibrate them to single radiation sources. It is advisable to check up the factual microbicidal effect of the nominal dosage by a biological dosimeter. The method reviewed potentiates a much higher confidence than that of conventional sterility tests and its additional advantage is the cheapness. (K.A.)

  5. Evaluation of various carbon blacks and dispersing agents for use in the preparation of uranium microspheres with carbon

    Science.gov (United States)

    Hunt, R. D.; Johnson, J. A.; Collins, J. L.; McMurray, J. W.; Reif, T. J.; Brown, D. R.

    2018-01-01

    A comparison study on carbon blacks and dispersing agents was performed to determine their impacts on the final properties of uranium fuel kernels with carbon. The main target compositions in this internal gelation study were 10 and 20 mol % uranium dicarbide (UC2), which is UC1.86, with the balance uranium dioxide. After heat treatment at 1900 K in flowing carbon monoxide in argon for 12 h, the density of the kernels produced using a X-energy proprietary carbon suspension, which is commercially available, ranged from 96% to 100% of theoretical density (TD), with full conversion of UC to UC2 at both carbon concentrations. However, higher carbon concentrations such as a 2.5 mol ratio of carbon to uranium in the feed solutions failed to produce gel spheres with the proprietary carbon suspension. The kernels using our former baseline of Mogul L carbon black and Tamol SN were 90-92% of TD with full conversion of UC to UC2 at a variety of carbon levels. Raven 5000 carbon black and Tamol SN were used to produce 10 mol % UC2 kernels with 95% of TD. However, an increase in the Raven 5000 concentration led to a kernel density below 90% of TD. Raven 3500 carbon black and Tamol SN were used to make very dense kernels without complete conversion to UC2. The selection of the carbon black and dispersing agent is highly dependent on the desired final properties of the target kernels.

  6. White and Black American Children’s Implicit Intergroup Bias

    Science.gov (United States)

    Newheiser, Anna-Kaisa; Olson, Kristina R.

    2011-01-01

    Despite a decline in explicit prejudice, adults and children from majority groups (e.g., White Americans) often express bias implicitly, as assessed by the Implicit Association Test. In contrast, minority-group (e.g., Black American) adults on average show no bias on the IAT. In the present research, representing the first empirical investigation of whether Black children’s IAT responses parallel those of Black adults, we examined implicit bias in 7–11-year-old White and Black American children. Replicating previous findings with adults, whereas White children showed a robust ingroup bias, Black children showed no bias. Additionally, we investigated the role of valuing status in the development of implicit bias. For Black children, explicit preference for high status predicted implicit outgroup bias: Black children who explicitly expressed high preference for rich (vs. poor) people showed an implicit preference for Whites comparable in magnitude to White children’s ingroup bias. Implications for research on intergroup bias are discussed. PMID:22184478

  7. Physico-chemical, microbial and sensory properties of kunu zaki beverage sweetened with black velvet tamarind (Dialium guineense)

    OpenAIRE

    Abiodun, O. A.; Dauda, A. O.; Adebisi, T. T.; Alonge, C. D.

    2017-01-01

    This work determined the physicochemical, microbial and sensory characteristics of kunu zaki sweetened with black velvet tamarind (Dialium guinnense) flour. The outer covering and seed of black velvet was removed while the pulp was pulverized to obtain the flour. The tamarind pulp was analysed for its proximate and sugar contents. Kunu zaki was prepared according to standard method and 10, 20, 30, 40 and 50 g of the black velvet pulp was added to 1000 ml each of kunu zaki along with a control...

  8. Structural, mechanical and electrical characterization of epoxy-amine/carbon black nanonocomposites

    Directory of Open Access Journals (Sweden)

    2008-05-01

    Full Text Available This work presents an insight into the effect of preparation procedure and the filler content on both electrical and mechanical properties of a nanocomposite system. For the preparation of the nanocomposites diglycidyl ether of bisphenol A (DGEBA was used with triethylenetetramine (TETA as a curing agent. As fillers carbon black (CB nanoparticles with size from 25 to 75 nm were used. The characterization was done using Dynamic Mechanical Analysis (DMA, Dielectric Relaxation Spectroscopy (DRS, Differential Scanning Calorimetry (DSC, Wide Angle X-ray Diffraction (WAXD and electrical conductivity measurements. The dependence of the dynamic mechanical and dielectric parameters (E′, E″, tanδ, ε', ε″, σ and Tg is associated with the filler content and is controlled by the employed curing conditions. An increase in electrical conductivity, which is observed at about 1% w/w of carbon black, indicates the creation of conducting paths and is associated with the Maxwell Wagner Sillars (MWS relaxation, probably due to the formation of aggregated microstructures in the bulk composite..

  9. Preparation, validation and user-testing of pictogram-based patient information leaflets for hemodialysis patients.

    Science.gov (United States)

    Mateti, Uday Venkat; Nagappa, Anantha Naik; Attur, Ravindra Prabhu; Bairy, Manohar; Nagaraju, Shankar Prasad; Mallayasamy, Surulivelrajan; Vilakkathala, Rajesh; Guddattu, Vasudev; Balkrishnan, Rajesh

    2015-11-01

    Patient information leaflets are universally-accepted resources to educate the patients/users about their medications, disease and lifestyle modification. The objective of the study was to prepare, validate and perform user-testing of pictogram-based patient information leaflets (P-PILs) among hemodialysis (HD) patients. The P-PILs are prepared by referring to the primary, secondary and tertiary resources. The content and pictograms of the leaflet have been validated by an expert committee consisting of three nephrologists and two academic pharmacists. The Baker Able Leaflet Design has been applied to develop the layout and design of the P-PILs. Quasi-experimental pre- and post-test design without control group was conducted on 81 HD patients for user-testing of P-PILs. The mean Baker Able Leaflet Design assessment score for English version of the leaflet was 28, and 26 for Kannada version. The overall user-testing knowledge assessment mean scores were observed to have significantly improved from 44.25 to 69.62 with p value information leaflets can be considered an effective educational tool for HD patients.

  10. Education and black-white interracial marriage.

    Science.gov (United States)

    Gullickson, Aaron

    2006-11-01

    This article examines competing theoretical claims regarding how an individual's education will affect his or her likelihood of interracial marriage. I demonstrate that prior models of interracial marriage have failed to adequately distinguish the joint and marginal effects of education on interracial marriage and present a model capable of distinguishing these effects. I test this model on black-white interracial marriages using 1980, 1990, and 2000 U.S. census data. The results reveal partial support for status exchange theory within black male-white female unions and strong isolation of lower-class blacks from the interracial marriage market. Structural assimilation theory is not supported because the educational attainment of whites is not related in any consistent fashion to the likelihood of interracial marriage. The strong isolation of lower-class blacks from the interracial marriage market has gone unnoticed in prior research because of the failure of prior methods to distinguish joint and marginal effects.

  11. Astrophysical flows near f(T) gravity black holes

    Energy Technology Data Exchange (ETDEWEB)

    Ahmed, Ayyesha K.; Jamil, Mubasher [National University of Sciences and Technology (NUST), Department of Mathematics, School of Natural Sciences (SNS), Islamabad (Pakistan); Azreg-Ainou, Mustapha [Baskent University, Baglica Campus, Engineering Faculty, Ankara (Turkey); Bahamonde, Sebastian [University College London, Department of Mathematics, London (United Kingdom); Capozziello, Salvatore [Universita di Napoli ' ' Federico II' ' , Dipartimento di Fisica, Naples (Italy); Gran Sasso Science Institute (INFN), L' Aquila (Italy); INFN Sezione di Napoli, Naples (Italy)

    2016-05-15

    In this paper, we study the accretion process for fluids flowing near a black hole in the context of f(T) teleparallel gravity. Specifically, by performing a dynamical analysis by a Hamiltonian system, we are able to find the sonic points. After that, we consider different isothermal test fluids in order to study the accretion process when they are falling onto the black hole. We find that these flows can be classified according to the equation of state and the black hole features. Results are compared in f(T) and f(R) gravity. (orig.)

  12. Last hired, first fired? Black-white unemployment and the business cycle.

    Science.gov (United States)

    Couch, Kenneth A; Fairlie, Robert

    2010-02-01

    Studies have tested the claim that blacks are the last hired during periods of economic growth and the first fired in recessions by examining the movement of relative unemployment rates over the business cycle. Any conclusion drawn from this type of analysis must be viewed as tentative because cyclical movements in the underlying transitions into and out of unemployment are not examined. Using Current Population Survey data matched across adjacent months from 1989-2004, this article provides the first detailed examination of labor market transitions for prime-age black and white men to test the last hired, first fired hypothesis. Considerable evidence is presented that blacks are the first fired as the business cycle weakens. However no evidence is found that blacks are the last hired. Instead, blacks appear to be initially hired from the ranks of the unemployed early in the business cycle and later are drawn from nonparticipation. The narrowing of the racial unemployment gap near the peak of the business cycle is driven by a reduction in the rate of job loss for blacks rather than increases in hiring.

  13. Stellar black holes and the origin of cosmic acceleration

    International Nuclear Information System (INIS)

    Prescod-Weinstein, Chanda; Afshordi, Niayesh; Balogh, Michael L.

    2009-01-01

    The discovery of cosmic acceleration has presented a unique challenge for cosmologists. As observational cosmology forges ahead, theorists have struggled to make sense of a standard model that requires extreme fine-tuning. This challenge is known as the cosmological constant problem. The theory of gravitational aether is an alternative to general relativity that does not suffer from this fine-tuning problem, as it decouples the quantum field theory vacuum from geometry, while remaining consistent with other tests of gravity. In this paper, we study static black hole solutions in this theory and show that it manifests a UV-IR coupling: Aether couples the space-time metric close to the black hole horizon, to metric at infinity. We then show that using the trans-Planckian ansatz (as a quantum gravity effect) close to the black hole horizon, leads to an accelerating cosmological solution, far from the horizon. Interestingly, this acceleration matches current observations for stellar-mass black holes. Based on our current understanding of the black hole accretion history in the Universe, we then make a prediction for how the effective dark energy density should evolve with redshift, which can be tested with future dark energy probes.

  14. Black holes

    OpenAIRE

    Brügmann, B.; Ghez, A. M.; Greiner, J.

    2001-01-01

    Recent progress in black hole research is illustrated by three examples. We discuss the observational challenges that were met to show that a supermassive black hole exists at the center of our galaxy. Stellar-size black holes have been studied in x-ray binaries and microquasars. Finally, numerical simulations have become possible for the merger of black hole binaries.

  15. The phase structure of higher-dimensional black rings and black holes

    International Nuclear Information System (INIS)

    Emparan, Roberto; Harmark, Troels; Niarchos, Vasilis; Obers, Niels A.; RodrIguez, Maria J.

    2007-01-01

    We construct an approximate solution for an asymptotically flat, neutral, thin rotating black ring in any dimension D ≥ 5 by matching the near-horizon solution for a bent boosted black string, to a linearized gravity solution away from the horizon. The rotating black ring solution has a regular horizon of topology S 1 x S D-3 and incorporates the balancing condition of the ring as a zero-tension condition. For D = 5 our method reproduces the thin ring limit of the exact black ring solution. For D ≥ 6 we show that the black ring has a higher entropy than the Myers-Perry black hole in the ultra-spinning regime. By exploiting the correspondence between ultra-spinning black holes and black membranes on a two-torus, we take steps towards qualitatively completing the phase diagram of rotating blackfolds with a single angular momentum. We are led to propose a connection between MP black holes and black rings, and between MP black holes and black Saturns, through merger transitions involving two kinds of 'pinched' black holes. More generally, the analogy suggests an infinite number of pinched black holes of spherical topology leading to a complicated pattern of connections and mergers between phases

  16. Slowly balding black holes

    International Nuclear Information System (INIS)

    Lyutikov, Maxim; McKinney, Jonathan C.

    2011-01-01

    The 'no-hair' theorem, a key result in general relativity, states that an isolated black hole is defined by only three parameters: mass, angular momentum, and electric charge; this asymptotic state is reached on a light-crossing time scale. We find that the no-hair theorem is not formally applicable for black holes formed from the collapse of a rotating neutron star. Rotating neutron stars can self-produce particles via vacuum breakdown forming a highly conducting plasma magnetosphere such that magnetic field lines are effectively ''frozen in'' the star both before and during collapse. In the limit of no resistivity, this introduces a topological constraint which prohibits the magnetic field from sliding off the newly-formed event horizon. As a result, during collapse of a neutron star into a black hole, the latter conserves the number of magnetic flux tubes N B =eΦ ∞ /(πc(ℎ/2π)), where Φ ∞ ≅2π 2 B NS R NS 3 /(P NS c) is the initial magnetic flux through the hemispheres of the progenitor and out to infinity. We test this theoretical result via 3-dimensional general relativistic plasma simulations of rotating black holes that start with a neutron star dipole magnetic field with no currents initially present outside the event horizon. The black hole's magnetosphere subsequently relaxes to the split-monopole magnetic field geometry with self-generated currents outside the event horizon. The dissipation of the resulting equatorial current sheet leads to a slow loss of the anchored flux tubes, a process that balds the black hole on long resistive time scales rather than the short light-crossing time scales expected from the vacuum no-hair theorem.

  17. The Geometry of Black Hole Singularities

    Directory of Open Access Journals (Sweden)

    Ovidiu Cristinel Stoica

    2014-01-01

    Full Text Available Recent results show that important singularities in General Relativity can be naturally described in terms of finite and invariant canonical geometric objects. Consequently, one can write field equations which are equivalent to Einstein's at nonsingular points but, in addition remain well-defined and smooth at singularities. The black hole singularities appear to be less undesirable than it was thought, especially after we remove the part of the singularity due to the coordinate system. Black hole singularities are then compatible with global hyperbolicity and do not make the evolution equations break down, when these are expressed in terms of the appropriate variables. The charged black holes turn out to have smooth potential and electromagnetic fields in the new atlas. Classical charged particles can be modeled, in General Relativity, as charged black hole solutions. Since black hole singularities are accompanied by dimensional reduction, this should affect Feynman's path integrals. Therefore, it is expected that singularities induce dimensional reduction effects in Quantum Gravity. These dimensional reduction effects are very similar to those postulated in some approaches to make Quantum Gravity perturbatively renormalizable. This may provide a way to test indirectly the effects of singularities, otherwise inaccessible.

  18. Yoghurt kedelai hitam (black soyghurt dapat menurunkan kadar LDL tikus hiperkolesterolemia

    Directory of Open Access Journals (Sweden)

    Slamet Riyanto

    2016-08-01

    Full Text Available ABSTRACTBackground: Hypercholesterolemia is a main risk factor of cardiovascular disease that remains the higher cause of deaths in the world. Black soy bean containing protein, fiber, vitamin, isoflavon, and flavonoid can decrease serum cholesterol level. Yoghurt contains lactic acid bacteria that decrease total and LDL cholesterol, triglyceride, and increase the HDL cholesterol. Processing of black soy bean into black soyghurt can increase its isoflavon’s activity by forming aglicone, which has higher activity to decrease cholesterol.Objectives: To know the effect of black soyghurt feeding to LDL, HDL, and HDL ratio of hypercholesterolemic rats.Methods: This research was true-experimental using post test only with control group design. Subjects were 20 male Sprague dawley rats, 2 months old, inducted hypercholesterolemia, given black soyghurt diet using 2 mL, 3 mL, and 4 mL dosage for 21 days. Serum lipid profile were measured by CHOD-PAPand GPO-PAP methods respectively. Normality of the data were tested by Shapiro Wilks test. Data were analyzed by paired t test and Anova continued by LSD test using computer program.Results: The study revealed that black soyghurt 4 mL/day decreased LDL (p=0.02 at the most significant level. The other doses did not significantly influence the levels of LDL (p>0.05 . There was also no effect of black soyghurt feeding on serum HDL cholesterol levels (p=0.11 and the ratio of LDL /HDL (p=0.087.Conclusions: The feeding of black soyghurt at the dosage of 4 mL/day to hypercholesterolemic rats could decrease the serum LDL, but could decrease the ratio of LDL / HDL significantly.KEYWORDS: black soyghurt, LDL/HDL ratio, hypercholesterolemicABSTRAKLatar belakang: Hiperkolesterolemia merupakan faktor risiko penyakit kardiovaskuler yang menjadi penyebab kematian utama di dunia. Kedelai hitam mengandung protein, vitamin, serat, isoflavon, dan flavonoid yang mampu menurunkan kadar kolesterol. Yoghurt

  19. On the Charter Question: Black Marxism and Black Nationalism

    Science.gov (United States)

    Stern, Mark; Hussain, Khuram

    2015-01-01

    This article brings two black intellectual traditions to bear on the question of charter schools: black Marxism and black nationalism. The authors examine the theoretical and rhetorical devices used to talk about charters schools by focusing on how notions of "black liberation" are deployed by the charter movement, and to what end. The…

  20. "Be Real Black for Me": Imagining BlackCrit in Education

    Science.gov (United States)

    Dumas, Michael J.; ross, kihana miraya

    2016-01-01

    The authors put forward a theorization of a Black Critical Theory, or what might be called BlackCrit, within, and in response to, Critical Race Theory, and then outline ways that BlackCrit in education helps us to more incisively analyze how the specificity of (anti)blackness matters in explaining how Black bodies become marginalized, disregarded,…

  1. Black hole astrophysics

    International Nuclear Information System (INIS)

    Blandford, R.D.; Thorne, K.S.

    1979-01-01

    Following an introductory section, the subject is discussed under the headings: on the character of research in black hole astrophysics; isolated holes produced by collapse of normal stars; black holes in binary systems; black holes in globular clusters; black holes in quasars and active galactic nuclei; primordial black holes; concluding remarks on the present state of research in black hole astrophysics. (U.K.)

  2. Spacetime and orbits of bumpy black holes

    International Nuclear Information System (INIS)

    Vigeland, Sarah J.; Hughes, Scott A.

    2010-01-01

    Our Universe contains a great number of extremely compact and massive objects which are generally accepted to be black holes. Precise observations of orbital motion near candidate black holes have the potential to determine if they have the spacetime structure that general relativity demands. As a means of formulating measurements to test the black hole nature of these objects, Collins and Hughes introduced ''bumpy black holes'': objects that are almost, but not quite, general relativity's black holes. The spacetimes of these objects have multipoles that deviate slightly from the black hole solution, reducing to black holes when the deviation is zero. In this paper, we extend this work in two ways. First, we show how to introduce bumps which are smoother and lead to better behaved orbits than those in the original presentation. Second, we show how to make bumpy Kerr black holes--objects which reduce to the Kerr solution when the deviation goes to zero. This greatly extends the astrophysical applicability of bumpy black holes. Using Hamilton-Jacobi techniques, we show how a spacetime's bumps are imprinted on orbital frequencies, and thus can be determined by measurements which coherently track the orbital phase of a small orbiting body. We find that in the weak field, orbits of bumpy black holes are modified exactly as expected from a Newtonian analysis of a body with a prescribed multipolar structure, reproducing well-known results from the celestial mechanics literature. The impact of bumps on strong-field orbits is many times greater than would be predicted from a Newtonian analysis, suggesting that this framework will allow observations to set robust limits on the extent to which a spacetime's multipoles deviate from the black hole expectation.

  3. Bioactive glass-ceramic coatings prepared by pulsed laser deposition from RKKP targets (sol-gel vs melt-processing route)

    Energy Technology Data Exchange (ETDEWEB)

    Rau, J.V., E-mail: giulietta.rau@ism.cnr.it [Istituto di Struttura della Materia, Consiglio Nazionale delle Ricerche, Via del Fosso del Cavaliere, 100-00133 Rome (Italy); Teghil, R. [Universita della Basilicata, Dipartimento di Chimica ' A.M. Tamburro' , Via dell' Ateneo Lucano, 10-85100 Potenza (Italy); CNR-IMIP U.O.S. di Potenza, Zona Industriale di Tito scalo (PZ) (Italy); Fosca, M. [Istituto di Struttura della Materia, Consiglio Nazionale delle Ricerche, Via del Fosso del Cavaliere, 100-00133 Rome (Italy); Universita di Roma ' La Sapienza' , Dipartimento di Chimica, Piazzale Aldo Moro, 5-00185 Rome (Italy); De Bonis, A. [Universita della Basilicata, Dipartimento di Chimica ' A.M. Tamburro' , Via dell' Ateneo Lucano, 10-85100 Potenza (Italy); CNR-IMIP U.O.S. di Potenza, Zona Industriale di Tito scalo (PZ) (Italy); Cacciotti, I.; Bianco, A. [Universita di Roma ' Tor Vergata' , Dipartimento di Ingegneria Industriale, UR INSTM ' Roma Tor Vergata' , Via del Politecnico, 1-00133 Rome (Italy); Albertini, V. Rossi [Istituto di Struttura della Materia, Consiglio Nazionale delle Ricerche, Via del Fosso del Cavaliere, 100-00133 Rome (Italy); Caminiti, R. [Universita di Roma ' La Sapienza' , Dipartimento di Chimica, Piazzale Aldo Moro, 5-00185 Rome (Italy); Ravaglioli, A. [Parco Torricelli delle Arti e delle Scienze, Via Granarolo, 64-48018 Faenza (Ra) (Italy)

    2012-05-15

    Highlights: Black-Right-Pointing-Pointer Bioactive glass-ceramic coatings for bone tissue repair and regeneration. Black-Right-Pointing-Pointer Pulsed Lased Deposition allowed congruent transfer of target composition to coating. Black-Right-Pointing-Pointer Target was prepared by sol-gel process suitable for compositional tailoring. Black-Right-Pointing-Pointer Titanium, widely used for orthopaedics and dental implants, was used as substrate. Black-Right-Pointing-Pointer The physico-chemical properties of the prepared coatings are reported. -- Abstract: The deposition of innovative glass-ceramic composition (i.e. RKKP) coatings by Pulsed Lased Deposition (PLD) technique is reported. RKKP was synthesised following two methodologies: melt-processing and sol-gel, the latter being particularly suitable to tailor the compositional range. The PLD advantage with respect to other deposition techniques is the congruent transfer of the target composition to the coating. The physico-chemical properties of films were investigated by Scanning Electron and Atomic Force Microscopies, Fourier Transform Infrared Spectroscopy, Angular and Energy Dispersive X-ray Diffraction, and Vickers microhardness. The deposition performed at 12 J/cm{sup 2} and 500 Degree-Sign C allows to prepare crystalline films with the composition that replicates rather well that of the initial targets. The 0.6 {mu}m thin melt-processing RKKP films, possessing the hardness of 25 GPa, and the 4.3 {mu}m thick sol-gel films with the hardness of 17 GPa were obtained.

  4. Preparation of a high strength Al-Cu-Mg alloy by mechanical alloying and press-forming

    Energy Technology Data Exchange (ETDEWEB)

    Tang Huaguo [State Key Laboratory of Rare Earth Utilization, Changchun Institute of Applied Chemistry, Chinese Academy of Sciences, Changchun 130022 (China); Cheng Zhiqiang [College of Resources and Environment, Jilin Agricultural University, Changchun 130118 (China); Liu Jianwei [State Key Laboratory of Rare Earth Utilization, Changchun Institute of Applied Chemistry, Chinese Academy of Sciences, Changchun 130022 (China); Ma Xianfeng, E-mail: xfma@ciac.jl.cn [State Key Laboratory of Rare Earth Utilization, Changchun Institute of Applied Chemistry, Chinese Academy of Sciences, Changchun 130022 (China)

    2012-07-30

    Highlights: Black-Right-Pointing-Pointer A high strength aluminum alloy of Al-2 wt.%Mg-2 wt.%Cu has been prepared by mechanical alloying and press-forming. Black-Right-Pointing-Pointer The alloy only consists of solid solution {alpha}-Al. Black-Right-Pointing-Pointer The grains size of {alpha}-Al was about 300 nm-5 {mu}m. Black-Right-Pointing-Pointer The solid solution strengthening and the grain refinement strengthening are the main reasons for such a high strength. - Abstract: A high strength aluminum alloy, with the ratio of 96 wt.%Al-2 wt.%Mg-2 wt.%Cu, has been prepared by mechanical alloying and press-forming. The alloy exhibited a high tensile strength of 780 MPa and a high microhardness of 180 HV. X-ray diffraction characterizations confirmed that the alloy only consists of a solid solution {alpha}-Al. Microstructure characterizations revealed that the grain size of {alpha}-Al was about 300 nm-5 {mu}m. The solid solution strengthening and the grain refinement strengthening were considered to be the reason for such a high strength.

  5. Gyromagnetic ratio of charged Kerr-anti-de Sitter black holes

    International Nuclear Information System (INIS)

    Aliev, Alikram N

    2007-01-01

    We examine the gyromagnetic ratios of rotating and charged AdS black holes in four and higher spacetime dimensions. We compute the gyromagnetic ratio for Kerr-AdS black holes with an arbitrary electric charge in four dimensions and show that it corresponds to g = 2 irrespective of the AdS nature of the spacetime. We also compute the gyromagnetic ratio for Kerr-AdS black holes with a single angular momentum and with a test electric charge in all higher dimensions. The gyromagnetic ratio crucially depends on the dimensionless ratio of the rotation parameter to the curvature radius of the AdS background. At the critical limit, when the boundary Einstein universe is rotating at the speed of light, it exhibits a striking feature leading to g 2 regardless of the spacetime dimension. Next, we extend our consideration to include the exact metric for five-dimensional rotating charged black holes in minimal gauged supergravity. We show that the value of the gyromagnetic ratio found in the 'test-charge' approach remains unchanged for these black holes

  6. Gender and Ethnic Differences in the Association Between Obesity and Depression Among Black Adolescents.

    Science.gov (United States)

    Assari, Shervin; Caldwell, Cleopatra Howard

    2015-12-01

    This study aimed to investigate the association between obesity and major depression disorder (MDD) in a nationally representative sample of Black adolescents in the USA. The study also tested the effects of ethnicity and gender as possible moderators. Data came from the National Survey of American Life (NSAL)-Adolescents, a representative household mental health survey of Black adolescents in the USA. Participants consisted of 1170 Black adolescents (810 African Americans and 360 Caribbean Blacks). Obesity was defined determined by the cutoff points based on the body mass index (BMI) appropriate for age and gender. Twelve-month MDD was measured using the World Mental Health Composite International Diagnostic Interview (CIDI). In the first step, the association between obesity and MDD in the pooled sample, controlling for the main effects of gender and ethnicity. In the next steps, two interactions were tested: (1) obesity and ethnicity and (2) obesity and gender. Although any associations between obesity and MDD in the pooled sample of Blacks were not found, there was a significant interaction between ethnicity and obesity on MDD. Upon testing the associations across intersections of ethnicity and gender, a positive association was found among Caribbean Black females but not Caribbean Black males, African American males, or African American female. The link between BMI and MDD among Blacks depends on ethnicity and gender, and risk of comorbid depression among Black youth with obesity is highest among Caribbean Black females.

  7. Sol-gel processed thin-layer ruthenium oxide/carbon black supercapacitors: A revelation of the energy storage issues

    Energy Technology Data Exchange (ETDEWEB)

    Panic, V.V.; Dekanski, A.B.; Stevanovic, R.M. [Institute of Chemistry, Technology and Metallurgy, Department of Electrochemistry, University of Belgrade, Njegoseva 12, Belgrade 125213 (RS)

    2010-07-01

    Hydrous ruthenium oxide/carbon black nanocomposites were prepared by impregnation of the carbon blacks by differently aged inorganic RuO{sub 2} sols, i.e. of different particle size. Commercial Black Pearls 2000 {sup registered} (BP) and Vulcan {sup registered} XC-72 R (XC) carbon blacks were used. Capacitive properties of BP/RuO{sub 2} and XC/RuO{sub 2} composites were investigated by cyclic voltammetry (CV) and electrochemical impedance spectroscopy (EIS) in H{sub 2}SO{sub 4} solution. Capacitance values and capacitance distribution through the composite porous layer were found different if high- (BP) and low- (XC) surface-area carbons are used as supports. The aging time (particle size) of Ru oxide sol as well as the concentration of the oxide solid phase in the impregnating medium influenced the capacitive performance of prepared composites. While the capacitance of BP-supported oxide decreases with the aging time, the capacitive ability of XC-supported oxide is promoted with increasing oxide particle size. The increase in concentration of the oxide solid phase in the impregnating medium caused an improvement of charging/discharging characteristics due to pronounced pseudocapacitance contribution of the increasing amount of inserted oxide. The effects of these variables in the impregnation process on the energy storage capabilities of prepared nanocomposites are envisaged as a result of intrinsic way of population of the pores of carbon material by hydrous Ru oxide particle. (author)

  8. Using measurements for evaluation of black carbon modeling

    Directory of Open Access Journals (Sweden)

    S. Gilardoni

    2011-01-01

    Full Text Available The ever increasing use of air quality and climate model assessments to underpin economic, public health, and environmental policy decisions makes effective model evaluation critical. This paper discusses the properties of black carbon and light attenuation and absorption observations that are the key to a reliable evaluation of black carbon model and compares parametric and nonparametric statistical tools for the quantification of the agreement between models and observations. Black carbon concentrations are simulated with TM5/M7 global model from July 2002 to June 2003 at four remote sites (Alert, Jungfraujoch, Mace Head, and Trinidad Head and two regional background sites (Bondville and Ispra. Equivalent black carbon (EBC concentrations are calculated using light attenuation measurements from January 2000 to December 2005. Seasonal trends in the measurements are determined by fitting sinusoidal functions and the representativeness of the period simulated by the model is verified based on the scatter of the experimental values relative to the fit curves. When the resolution of the model grid is larger than 1° × 1°, it is recommended to verify that the measurement site is representative of the grid cell. For this purpose, equivalent black carbon measurements at Alert, Bondville and Trinidad Head are compared to light absorption and elemental carbon measurements performed at different sites inside the same model grid cells. Comparison of these equivalent black carbon and elemental carbon measurements indicates that uncertainties in black carbon optical properties can compromise the comparison between model and observations. During model evaluation it is important to examine the extent to which a model is able to simulate the variability in the observations over different integration periods as this will help to identify the most appropriate timescales. The agreement between model and observation is accurately described by the overlap of

  9. Selection of dissolution process for spent fuels and preparation of corrosion test solution simulated to dissolver (contract research)

    International Nuclear Information System (INIS)

    Motooka, Takafumi; Terakado, Shogo; Koya, Toshio; Hamada, Shozo; Kiuchi, Kiyoshi

    2001-03-01

    In order to evaluate the reliability of reprocessing equipment materials used in the Rokkasho Reprocessing Plant, we have proceeded a mock-up test and laboratory tests for getting corrosion parameters. In a dissolver made of zirconium, the simulation of test solutions to the practical solution which includes the high concentration of radioactive elements such as FP and TRU is one of the important issues with respect to the life prediction. On this experiment, the dissolution process of spent fuels and the preparation of test solution for evaluating the corrosion resistance of dissolver materials were selected. These processes were tested in the No.3 cell of WASTEF. The test solution for corrosion tests was prepared by adjusting the uranium and nitric acid concentrations. (author)

  10. Towards a formalism for mapping the spacetimes of massive compact objects: Bumpy black holes and their orbits

    International Nuclear Information System (INIS)

    Collins, Nathan A.; Hughes, Scott A.

    2004-01-01

    Astronomical observations have established that extremely compact, massive objects are common in the Universe. It is generally accepted that these objects are, in all likelihood, black holes. As observational technology has improved, it has become possible to test this hypothesis in ever greater detail. In particular, it is or will be possible to measure the properties of orbits deep in the strong field of a black hole candidate (using x-ray timing or future gravitational-wave measurements) and to test whether they have the characteristics of black hole orbits in general relativity. Past work has shown that, in principle, such measurements can be used to map the spacetime of a massive compact object, testing in particular whether the object's multipolar structure satisfies the rather strict constraints imposed by the black hole hypothesis. Performing such a test in practice requires that we be able to compare against objects with the 'wrong' multipole structure. In this paper, we present tools for constructing the spacetimes of bumpy black holes: objects that are almost black holes, but that have some multipoles with the wrong value. In this first analysis, we focus on objects with no angular momentum. Generalization to bumpy Kerr black holes should be straightforward, albeit labor intensive. Our construction has two particularly desirable properties. First, the spacetimes which we present are good deep into the strong field of the object--we do not use a 'large r' expansion (except to make contact with weak field intuition). Second, our spacetimes reduce to the exact black hole spacetimes of general relativity in a natural way, by dialing the 'bumpiness' of the black hole to zero. We propose that bumpy black holes can be used as the foundation for a null experiment: if black hole candidates are indeed the black holes of general relativity, their bumpiness should be zero. By comparing the properties of orbits in a bumpy spacetime with those measured from an

  11. Do black-furred animals compensate for high solar absorption with smaller hairs? A test with a polymorphic squirrel species

    Directory of Open Access Journals (Sweden)

    Melanie A. FRATTO, Andrew K. DAVIS

    2011-12-01

    Full Text Available In polymorphic mammalian species that display multiple color forms, those with dark, or melanic pelage would be prone to overheating, especially if they live in warm climates, because their fur absorbs solar energy at a higher rate. However, experimental studies indicate that certain physical properties of fur of dark individuals appear to prevent, or minimize heat stress, although it is not clear what properties do so. Here, we tested the possibility that black-furred individuals simply have shorter or thinner hair fibers, which would create a lighter (in terms of weight coat or one that allows greater air flow for evaporative coo- ling. We examined museum specimens of eastern fox squirrels Sciurus niger, a species native to the United States and one that displays brown, grey or all-black pelage color, and used image analysis procedures to quantify hairs from the dorsal surface and tail. From examination of 43 specimens (19 brown, 9 black and 15 grey, and 1,720 hairs, we found no significant difference in hair lengths across color morphs, but significant differences in hair fiber widths. Black squirrels had thinner body hairs than other forms (7% thinner, but thicker tail hairs (9% thicker than the others. Given that the dorsal surface would be directly exposed to solar radiation, we interpret this to be an adaptation to prevent heat stress during the day. The thicker tail hairs may be an adaptation for nighttime thermoregulation, since squirrels sleep with their tails wrapped around their bodies. These results add to a growing literature body of the functional significance of mammalian pelage [Current Zoology 57 (6: 731–736, 2011].

  12. Massive Black Holes and Galaxies

    CERN Multimedia

    CERN. Geneva

    2016-01-01

    Evidence has been accumulating for several decades that many galaxies harbor central mass concentrations that may be in the form of black holes with masses between a few million to a few billion time the mass of the Sun. I will discuss measurements over the last two decades, employing adaptive optics imaging and spectroscopy on large ground-based telescopes that prove the existence of such a massive black hole in the Center of our Milky Way, beyond any reasonable doubt. These data also provide key insights into its properties and environment. Most recently, a tidally disrupting cloud of gas has been discovered on an almost radial orbit that reached its peri-distance of ~2000 Schwarzschild radii in 2014, promising to be a valuable tool for exploring the innermost accretion zone. Future interferometric studies of the Galactic Center Black hole promise to be able to test gravity in its strong field limit.

  13. Teachers' perceptions of the effectiveness of an urban health sciences curriculum in closing the Black-White test score gap: A participatory case study

    Science.gov (United States)

    Prince, Joan Marie

    1999-12-01

    Over the past years, progress in Black academic achievement, particularly in the area of science, has generally slowed or ceased. According to the 1994 NAEP assessment, twelfth-grade Black students are performing at the level of White eighth-grade students in the discipline of science (Department of Education, 1996). These students, in their last year of required schooling, are about to graduate, yet they lag at least four years behind their white counterparts in science achievement. Despite the establishment and implementation of numerous science intervention programs, Black students still suffer from a disparate gap in standardized test score achievement. The purpose of this research is to investigate teachers' perceptions of the effectiveness of an urban sciences intervention tool that was designed to assist in narrowing the Black-White science academic achievement gap. Specifically, what factors affect teachers' personal sense of instructional efficacy, and how does this translate into their outcome expectancy for student academic success? A multiple-case, replicative design, grounded in descriptive theory, was selected for the study. Multiple sources of evidence were queried to provide robust findings. These sources included a validated health sciences self-efficacy instrument, an interview protocol, a classroom observation, and a review of archival material that included case study participants' personnel files and meeting minutes. A cross-comparative analytic approach was selected for interpretation (Yin, 1994). Findings indicate that teachers attribute the success or failure of educational intervention tools in closing the Black-White test score gap to a variety of internal and external factors. These factors included a perceived lack of both monetary and personal support by the school leadership, as well as a perceived lack of parental involvement which impacted negatively on student achievement patterns. The case study participants displayed a depressed

  14. 40 CFR 1048.410 - How must I select, prepare, and test my in-use engines?

    Science.gov (United States)

    2010-07-01

    ... my in-use engines? 1048.410 Section 1048.410 Protection of Environment ENVIRONMENTAL PROTECTION AGENCY (CONTINUED) AIR POLLUTION CONTROLS CONTROL OF EMISSIONS FROM NEW, LARGE NONROAD SPARK-IGNITION ENGINES Testing In-use Engines § 1048.410 How must I select, prepare, and test my in-use engines? (a) You...

  15. Contemporary Black Theatre.

    Science.gov (United States)

    Thomas, Pearl

    The distinguishable black theatre in America, mirroring a distinguishable black experience, is an artistic product which demands audience involvement. Both the Afro-American oral tradition and the art of gesture are integral aspects of black theatre. In addition, the tragedy found black theatre is not tragedy in the classic sense, as blacks feel…

  16. Investing in Diversity in London Schools: Leadership Preparation for Black and Global Majority Educators

    Science.gov (United States)

    Johnson, Lauri; Campbell-Stephens, Rosemary

    2010-01-01

    This article traces the historical roots, describes the philosophy and curriculum, and analyzes the approach to leadership in Investing in Diversity, a 1-year Black-led leadership development course in the London schools. An exploratory qualitative case study approach was used to collect historical and empirical data about the program over a…

  17. Caged black holes: Black holes in compactified spacetimes. I. Theory

    International Nuclear Information System (INIS)

    Kol, Barak; Sorkin, Evgeny; Piran, Tsvi

    2004-01-01

    In backgrounds with compact dimensions there may exist several phases of black objects including a black hole and a black string. The phase transition between them raises questions and touches on fundamental issues such as topology change, uniqueness, and cosmic censorship. No analytic solution is known for the black hole, and moreover one can expect approximate solutions only for very small black holes, while phase transition physics happens when the black hole is large. Hence we turn to numerical solutions. Here some theoretical background to the numerical analysis is given, while the results will appear in a subsequent paper. The goals for a numerical analysis are set. The scalar charge and tension along the compact dimension are defined and used as improved order parameters which put both the black hole and the black string at finite values on the phase diagram. The predictions for small black holes are presented. The differential and the integrated forms of the first law are derived, and the latter (Smarr's formula) can be used to estimate the 'overall numerical error'. Field asymptotics and expressions for physical quantities in terms of the numerical values are supplied. The techniques include the 'method of equivalent charges', free energy, dimensional reduction, and analytic perturbation for small black holes

  18. Relativistic hydrodynamics in the presence of puncture black holes

    International Nuclear Information System (INIS)

    Faber, Joshua A.; Etienne, Zachariah B.; Shapiro, Stuart L.; Taniguchi, Keisuke; Baumgarte, Thomas W.

    2007-01-01

    Many of the recent numerical simulations of binary black holes in vacuum adopt the moving puncture approach. This successful approach avoids the need to impose numerical excision of the black hole interior and is easy to implement. Here we wish to explore how well the same approach can be applied to moving black hole punctures in the presence of relativistic hydrodynamic matter. First, we evolve single black hole punctures in vacuum to calibrate our Baumgarte-Shapiro-Shibata-Nakamura implementation and to confirm that the numerical solution for the exterior spacetime is invariant to any junk (i.e., constraint-violating) initial data employed in the black hole interior. Then we focus on relativistic Bondi accretion onto a moving puncture Schwarzschild black hole as a numerical test bed for our high-resolution shock-capturing relativistic hydrodynamics scheme. We find that the hydrodynamical equations can be evolved successfully in the interior without imposing numerical excision. These results help motivate the adoption of the moving puncture approach to treat the binary black hole-neutron star problem using conformal thin-sandwich initial data

  19. Primary black holes

    International Nuclear Information System (INIS)

    Novikov, I.; Polnarev, A.

    1981-01-01

    Proves are searched for of the formation of the so-called primary black holes at the very origin of the universe. The black holes would weigh less than 10 13 kg. The formation of a primary black hole is conditional on strong fluctuations of the gravitational field corresponding roughly to a half of the fluctuation maximally permissible by the general relativity theory. Only big fluctuations of the gravitational field can overcome the forces of the hot gas pressure and compress the originally expanding matter into a black hole. Low-mass black holes have a temperature exceeding that of the black holes formed from stars. A quantum process of particle formation, the so-called evaporation takes place in the strong gravitational field of a black hole. The lower the mass of the black hole, the shorter the evaporation time. The analyses of processes taking place during the evaporation of low-mass primary black holes show that only a very small proportion of the total mass of the matter in the universe could turn into primary black holes. (M.D.)

  20. Drop formation of black liquor spraying; Mustalipeaen pisaroituminen

    Energy Technology Data Exchange (ETDEWEB)

    Fogelholm, C J; Kankkunen, A; Nieminen, K; Laine, J; Miikkulainen, P [Helsinki Univ. of Technology, Otaniemi (Finland): Lab. of Energy Technology and Environmental Protection

    1997-10-01

    Black liquor is a spent liquor of the pulp and paper industry. It is burned in kraft recovery boilers for chemical and energy recovery. The high dry solids content and viscosity of black liquor require a high spraying temperature. This affects the performance of the boiler. Kraft recovery boiler deposit formation, emissions and chemical recovery are strongly affected by the drop size and the velocity of the black liquor spray formed by a splashplate nozzle. The sheet breakup mechanism is studied with a system based on a video and image-analysis. The drop size of mill-scale nozzles was measured also with an image-analysis-system. Measurements were carried out in a spray test chamber. The sheet breakup mechanism and drop size tests were carried out both below and over the boiling point of black liquor. Special attention was paid to the effect of flashing on drop formation. Temperature increase normally decreases drop size. In the temperature where the wavy-sheet disintegration changes to perforated-sheet disintegration the drop size increases. Spray velocity rises when the temperature is increased above the boiling point. (orig.)

  1. 77 FR 70423 - Black Bear Hydro Partners, LLC and Black Bear Development Holdings, LLC and Black Bear SO, LLC...

    Science.gov (United States)

    2012-11-26

    ... Bear Hydro Partners, LLC and Black Bear Development Holdings, LLC and Black Bear SO, LLC; Notice of..., 2012, Black Bear Hydro Partners, LLC, sole licensee (transferor) and Black Bear Development Holdings, LLC and Black Bear SO, LLC (transferees) filed an application for the partial the transfer of licenses...

  2. Preparation polystyrene/multiwalled carbon nanotubes nanocomposites by copolymerization of styrene and styryl-functionalized multiwalled carbon nanotubes

    Energy Technology Data Exchange (ETDEWEB)

    Hua, Jing, E-mail: huajing72@qust.edu.cn [Key Laboratory of Rubber-Plastics Ministry of Education, Qingdao University of Science and Technology, Qingdao (China); Wang, Zhongguang; Xu, Ling; Wang, Xin; Zhao, Jian; Li, Feifei [Key Laboratory of Rubber-Plastics Ministry of Education, Qingdao University of Science and Technology, Qingdao (China)

    2013-01-15

    Styryl-functionalized multiwalled carbon nanotubes (p-MWNTs) were prepared by esterification based on the carboxylate salt of carbon nanotubes and p-chloromethylstyrene in toluene. Then in situ radical copolymerization of p-MWNTs and styrene initiated by 2,2 Prime -azobis(isobutyronitrile) (AIBN) was applied to synthesize composites of styryl-functionalized multiwalled carbon nanotubes and polystyrene (PS) (p-MWNTs/PS). Characterizations carried out by FT-IR, {sup 1}H NMR, UV-vis show that styryl group covalently bond to the surface of MWNTs. The results of UV showed that the solutions of p-MWNTs/PS in chloroform have the hyperchromic effect. Transmission electron microscopy (TEM) images of p-MWNTs/PS composites and scanning electron microscopy (SEM) images of fracture surface of p-MWNTs/PS composites showed the functionalized nanotubes had a better dispersion than that of the unfunctionalized MWNTs in the matrix. The results of thermogravimetric analysis (TGA) and differential scanning calorimetry (DSC) suggested that the thermal stability of p-MWNTs/PS composites improved in the presence of MWNTs. -- Highlights: Black-Right-Pointing-Pointer A facile and simple way to successfully prepare the polystyrene/MWNTs nanocomposites. Black-Right-Pointing-Pointer Characterizations show that styryl group covalently bond to the surface of MWNTs. Black-Right-Pointing-Pointer The solutions of p-MWNTs/PS in chloroform have the hyperchromic effect. Black-Right-Pointing-Pointer Thermal stability of p-tpas composites improved in the presence of MWNTs. Black-Right-Pointing-Pointer The performance of polymer prepared by this method have great potential for exploitation.

  3. DNA barcode identification of black cohosh herbal dietary supplements.

    Science.gov (United States)

    Baker, David A; Stevenson, Dennis W; Little, Damon P

    2012-01-01

    Black cohosh (Actaea racemosa) herbal dietary supplements are commonly consumed to treat menopausal symptoms, but there are reports of adverse events and toxicities associated with their use. Accidental misidentification and/or deliberate adulteration results in harvesting other related species that are then marketed as black cohosh. Some of these species are known to be toxic to humans. We have identified two matK nucleotides that consistently distinguish black cohosh from related species. Using these nucleotides, an assay was able to correctly identify all of the black cohosh samples in the validation set. None of the other Actaea species in the validation set were falsely identified as black cohosh. Of 36 dietary supplements sequenced, 27 (75%) had a sequence that exactly matched black cohosh. The remaining nine samples (25%) had a sequence identical to that of three Asian Actaea species (A. cimicifuga, A. dahurica, and A. simplex). Manufacturers should routinely test plant material using a reliable assay to ensure accurate labeling.

  4. Effective photon mass from black-hole formation

    Directory of Open Access Journals (Sweden)

    Slava Emelyanov

    2017-06-01

    Full Text Available We compute the value of effective photon mass mγ at one-loop level in QED in the background of small (1010 g≲M≪1016 g spherically symmetric black hole in asymptotically flat spacetime. This effect is associated with the modification of electron/positron propagator in presence of event horizon. Physical manifestations of black-hole environment are compared with those of hot neutral plasma. We estimate the distance to the nearest black hole from the upper bound on mγ obtained in the Coulomb-law test. We also find that corrections to electron mass me and fine structure constant α at one-loop level in QED are negligible in the weak gravity regime.

  5. Comparison: Binomial model and Black Scholes model

    Directory of Open Access Journals (Sweden)

    Amir Ahmad Dar

    2018-03-01

    Full Text Available The Binomial Model and the Black Scholes Model are the popular methods that are used to solve the option pricing problems. Binomial Model is a simple statistical method and Black Scholes model requires a solution of a stochastic differential equation. Pricing of European call and a put option is a very difficult method used by actuaries. The main goal of this study is to differentiate the Binominal model and the Black Scholes model by using two statistical model - t-test and Tukey model at one period. Finally, the result showed that there is no significant difference between the means of the European options by using the above two models.

  6. STU black holes and SgrA{sup *}

    Energy Technology Data Exchange (ETDEWEB)

    Cvetič, M. [Department of Physics and Astronomy, University of Pennsylvania, Philadelphia, PA 19104 (United States); Gibbons, G.W.; Pope, C.N., E-mail: cvetic@physics.upenn.edu, E-mail: gwg1@cam.ac.uk, E-mail: pope@physics.tamu.edu [DAMTP, Centre for Mathematical Sciences, Cambridge University, Wilberforce Road, Cambridge CB3 OWA (United Kingdom)

    2017-08-01

    The equations of null geodesics in the STU family of rotating black hole solutions of supergravity theory, which may be considered as deformations of the vacuum Kerr metric, are completely integrable. We propose that they be used as a foil to test, for example, with what precision the gravitational field external to the black hole at the centre of our galaxy is given by the Kerr metric. By contrast with some metrics proposed in the literature, the STU metrics satisfy by construction the dominant and strong energy conditions. Our considerations may be extended to include the effects of a cosmological term. We show that these metrics permit a straightforward calculation of the properties of black hole shadows.

  7. The Evolution of the Black-White Test Score Gap in Grades K-3: The Fragility of Results. NBER Working Paper No. 17960

    Science.gov (United States)

    Bond, Timothy N.; Lang, Kevin

    2012-01-01

    Although both economists and psychometricians typically treat them as interval scales, test scores are reported using ordinal scales. Using the Early Childhood Longitudinal Study and the Children of the National Longitudinal Survey, we examine the effect of order-preserving scale transformations on the evolution of the black-white reading test…

  8. Phase transition for black holes with scalar hair and topological black holes

    International Nuclear Information System (INIS)

    Myung, Yun Soo

    2008-01-01

    We study phase transitions between black holes with scalar hair and topological black holes in asymptotically anti-de Sitter spacetimes. As the ground state solutions, we introduce the non-rotating BTZ black hole in three dimensions and topological black hole with hyperbolic horizon in four dimensions. For the temperature matching only, we show that the phase transition between black hole with scalar hair (Martinez-Troncoso-Zanelli black hole) and topological black hole is second-order by using differences between two free energies. However, we do not identify what order of the phase transition between scalar and non-rotating BTZ black holes occurs in three dimensions, although there exists a possible decay of scalar black hole to non-rotating BTZ black hole

  9. Black germanium selective absorber surfaces. Final technical report, September 1, 1978-June 30, 1979

    Energy Technology Data Exchange (ETDEWEB)

    Messier, R.; Vedam, K.; Krishnaswamy, S.V.

    1979-12-01

    Semiconductor films with an appropriate band gap (approx. 0.5 to 1.25 ev) have a high absorption coefficient in the solar spectrum region and high transmission in the IR thermal-emission region and thus make nearly ideal selective absorbers. However, due to their high refractive index, semiconductor films have high reflectance above their absorption edge which limits their total absorption. A coating which would retain the advantages of the semiconductor's selectivity and also reduce the reflectance from the present values of 30 to 50% to a level of less than 2% would be a significant advancement in the state of the art. This study describes work on the preparation and characterization of structurally anisotropic black Ge films by rf-sputtering and postdeposition etching. It has been shown that by controlling the sputtering preparation conditions of noncrystalline Ge films the surface microstructure can be drastically altered by simply etching in 30% H/sub 2/O/sub 2/. The total reflectance of the resulting surface was reduced from about 45% to less than 1%. Furthermore, the films appear black over a wide range of angles of incidence ( up to 45% from the normal). This flat black appearance is shown to be due to a dense array of aligned, needle-like protrusions which have an extremely high aspect ratio and both a cross-sectional area and a separation between the needles on th order of the wavelength of solar radiation. Black Ge films were obtained with a solar absorptance, ..cap alpha../sub S/, of greater than 0.99 in the best cases. Variation of ..cap alpha../sub S/ and epsilon/sub IR/ (IR emittance) with the thickness of the film and other preparation conditions is described. Further, the various microstructures are classified and understood on the basis of a structure zone model.

  10. From binary black hole simulation to triple black hole simulation

    International Nuclear Information System (INIS)

    Bai Shan; Cao Zhoujian; Han, Wen-Biao; Lin, Chun-Yu; Yo, Hwei-Jang; Yu, Jui-Ping

    2011-01-01

    Black hole systems are among the most promising sources for a gravitational wave detection project. Now, China is planning to construct a space-based laser interferometric detector as a follow-on mission of LISA in the near future. Aiming to provide some theoretical support to this detection project on the numerical relativity side, we focus on black hole systems simulation in this work. Considering the globular galaxy, multiple black hole systems also likely to exist in our universe and play a role as a source for the gravitational wave detector we are considering. We will give a progress report in this paper on our black hole system simulation. More specifically, we will present triple black hole simulation together with binary black hole simulation. On triple black hole simulations, one novel perturbational method is proposed.

  11. Effects of various defects on the mechanical properties of black phosphorene

    Science.gov (United States)

    Nguyen, Danh-Truong; Le, Minh-Quy; Nguyen, Van-Trang; Bui, Thanh-Lam

    2017-12-01

    The present work investigates the effects of seven types of defects on the mechanical properties of black phosphorene. Molecular dynamics finite element method with Stillinger-Weber potential is used to simulate the uniaxial tensile tests of the pristine and defective black phosphorene sheets. Young's modulus, fracture stress, and fracture strain of the pristine and defective black phosphorene sheets are estimated. Comparison of the influence of different types of defects on the mechanical response of black phosphorene is considered. Fracture mechanism of various defective black phosphorene sheets is also analyzed. It is found that effect of the defects on Young's modulus of black phosphorene is insignificant. In contrast, due to defects fracture stress and fracture strain can reduce up to 53% and 69%, respectively. Results provide a landscape on the mechanical properties of defective black phosphorene and are useful for the design of nanodevices with black phosphorene in future applications.

  12. Surface geometry of 5D black holes and black rings

    International Nuclear Information System (INIS)

    Frolov, Valeri P.; Goswami, Rituparno

    2007-01-01

    We discuss geometrical properties of the horizon surface of five-dimensional rotating black holes and black rings. Geometrical invariants characterizing these 3D geometries are calculated. We obtain a global embedding of the 5D rotating black horizon surface into a flat space. We also describe the Kaluza-Klein reduction of the black ring solution (along the direction of its rotation) which, though it is nakedly singular, relates this solution to the 4D metric of a static black hole distorted by the presence of external scalar (dilaton) and vector ('electromagnetic') fields. The properties of the reduced black hole horizon and its embedding in E 3 are briefly discussed

  13. Thermodynamics of intersecting black branes from interacting elementary branes

    Energy Technology Data Exchange (ETDEWEB)

    Morita, Takeshi [Department of Physics, Shizuoka University,836 Ohya, Suruga-ku, Shizuoka 422-8529 (Japan); Shiba, Shotaro [Maskawa Institute for Science and Culture, Kyoto Sangyo University,Kamigamo-Motoyama, Kita-ku, Kyoto 603-8555 (Japan)

    2015-09-14

    If an Einstein-Maxwell-Dilaton system admits the extreme brane solution in which no force works between the parallel branes, the collective motion of nearly parallel branes exhibits the thermodynamical properties which are coincident with those of the corresponding black branes at low energy regime (up to unfixed numerical factors). Hence it may provide the microscopic description of the black branes (p-soup proposal). This fact motivates us to test this proposal in the intersecting black branes which have multiple brane charges and/or momentum along the brane direction. We consider the case that the multiple branes satisfy the intersection rule and feel no force when they are static, and find the agreement to the black hole thermodynamics.

  14. Advancement of High Temperature Black Liquor Gasification Technology

    Energy Technology Data Exchange (ETDEWEB)

    Craig Brown; Ingvar Landalv; Ragnar Stare; Jerry Yuan; Nikolai DeMartini; Nasser Ashgriz

    2008-03-31

    Weyerhaeuser operates the world's only commercial high-temperature black liquor gasifier at its pulp mill in New Bern, NC. The unit was started-up in December 1996 and currently processes about 15% of the mill's black liquor. Weyerhaeuser, Chemrec AB (the gasifier technology developer), and the U.S. Department of Energy recognized that the long-term, continuous operation of the New Bern gasifier offered a unique opportunity to advance the state of high temperature black liquor gasification toward the commercial-scale pressurized O2-blown gasification technology needed as a foundation for the Forest Products Bio-Refinery of the future. Weyerhaeuser along with its subcontracting partners submitted a proposal in response to the 2004 joint USDOE and USDA solicitation - 'Biomass Research and Development Initiative'. The Weyerhaeuser project 'Advancement of High Temperature Black Liquor Gasification' was awarded USDOE Cooperative Agreement DE-FC26-04NT42259 in November 2004. The overall goal of the DOE sponsored project was to utilize the Chemrec{trademark} black liquor gasification facility at New Bern as a test bed for advancing the development status of molten phase black liquor gasification. In particular, project tasks were directed at improvements to process performance and reliability. The effort featured the development and validation of advanced CFD modeling tools and the application of these tools to direct burner technology modifications. The project also focused on gaining a fundamental understanding and developing practical solutions to address condensate and green liquor scaling issues, and process integration issues related to gasifier dregs and product gas scrubbing. The Project was conducted in two phases with a review point between the phases. Weyerhaeuser pulled together a team of collaborators to undertake these tasks. Chemrec AB, the technology supplier, was intimately involved in most tasks, and focused primarily on the

  15. Testing the Kerr Black Hole Hypothesis Using X-Ray Reflection Spectroscopy

    Energy Technology Data Exchange (ETDEWEB)

    Bambi, Cosimo; Nampalliwar, Sourabh [Center for Field Theory and Particle Physics and Department of Physics, Fudan University, 200433 Shanghai (China); Cárdenas-Avendaño, Alejandro [Programa de Matemática, Fundación Universitaria Konrad Lorenz, 110231 Bogotá (Colombia); Dauser, Thomas [Remeis Observatory and ECAP, Universität Erlangen-Nürnberg, D-96049 Bamberg (Germany); García, Javier A., E-mail: bambi@fudan.edu.cn [Harvard-Smithsonian Center for Astrophysics, Cambridge, MA 02138 (United States)

    2017-06-20

    We present the first X-ray reflection model for testing the assumption that the metric of astrophysical black holes is described by the Kerr solution. We employ the formalism of the transfer function proposed by Cunningham. The calculations of the reflection spectrum of a thin accretion disk are split into two parts: the calculation of the transfer function and the calculation of the local spectrum at any emission point in the disk. The transfer function only depends on the background metric and takes into account all the relativistic effects (gravitational redshift, Doppler boosting, and light bending). Our code computes the transfer function for a spacetime described by the Johannsen metric and can easily be extended to any stationary, axisymmetric, and asymptotically flat spacetime. Transfer functions and single line shapes in the Kerr metric are compared to those calculated from existing codes to check that we reach the necessary accuracy. We also simulate some observations with NuSTAR and LAD/eXTP and fit the data with our new model to show the potential capabilities of current and future observations to constrain possible deviations from the Kerr metric.

  16. Black Holes

    OpenAIRE

    Townsend, P. K.

    1997-01-01

    This paper is concerned with several not-quantum aspects of black holes, with emphasis on theoretical and mathematical issues related to numerical modeling of black hole space-times. Part of the material has a review character, but some new results or proposals are also presented. We review the experimental evidence for existence of black holes. We propose a definition of black hole region for any theory governed by a symmetric hyperbolic system of equations. Our definition reproduces the usu...

  17. Black silicon solar cells with black bus-bar strings

    DEFF Research Database (Denmark)

    Davidsen, Rasmus Schmidt; Tang, Peter Torben; Mizushima, Io

    2016-01-01

    We present the combination of black silicon texturing and blackened bus-bar strings as a potential method for obtaining all-black solar panels, while using conventional, front-contacted solar cells. Black silicon was realized by maskless reactive ion etching resulting in total, average reflectance...... below 0.5% across a 156x156 mm2 silicon wafer. Four different methods to obtain blackened bus-bar strings were compared with respect to reflectance, and two of these methods (i.e., oxidized copper and etched solder) were used to fabricate functional allblack solar 9-cell panels. The black bus-bars (e.......g., by oxidized copper) have a reflectance below 3% in the entire visible wavelength range. The combination of black silicon cells and blackened bus-bars results in aesthetic, all-black panels based on conventional, front-contacted solar cells without compromising efficiency....

  18. Further Rehabilitating CIV-based Black Hole Mass Estimates in Quasars

    Science.gov (United States)

    Brotherton, Michael S.; Runnoe, Jessie C.; Shang, Zhaohui; Varju, Melinda

    2016-06-01

    Virial black hole masses are routinely estimated for high-redshift quasars using the C IV lambda 1549 emission line using single-epoch spectra that provide a gas velocity and a continuum luminosity. Such masses are very uncertain, however, especially because C IV likely possesses a non-virial component that varies with the Eddington ratio. We have previously used the 1400 feature, a blend of S i IV and O IV] emission that does not suffer the problems of C IV, to rehabilitate C IV-based mases by providing a correction term. The C IV profile itself, however, provides enough information to correct the black hole masses and remove the effects of the non-virial component. We use Mg II-based black hole masses to calibrate and test a new C IV-based black hole mass formula using only C IV and continuum measurements superior to existing formulations, as well as to test for additional dependencies on luminosity.

  19. Residential radon in Kansas City-black shales aren't the prime suspect

    International Nuclear Information System (INIS)

    Spencer, C.G.

    1993-01-01

    The US EPA preliminary assessment of potential radon risk (EPA, 1986) depicted a large area of the mid-continent in which radon levels might be elevated due to the presence of uranium-rich black shales. A preliminary study (Hilpman, Coveney ampersand Spencer, 1988) indicated that a significant percentage of homes in the greater Kansas City area had radon screening levels above 4 pCi/L. However, their lab tests with crushed black shale, and radon tests in limestone mines with black shale floors showed that the shale did not yield extremely high radon levels. This expanded study presents additional results of screening tests in homes, and correlates those results to bedrock geology and soil type. High radon levels in the Kansas city area are not due primarily to black shale sources. The highest readings are associated with limestone and non-organic shale. Mean radon level is higher in younger cyclothemic deposits, and a loessial soil. The EPA initial assessment overstated the radon risk attributable to black uraniferous shale sources. Assessment of the overall potential risk for the greater Kansas City area requires further evaluation of other sources

  20. Black hole spectroscopy: Systematic errors and ringdown energy estimates

    Science.gov (United States)

    Baibhav, Vishal; Berti, Emanuele; Cardoso, Vitor; Khanna, Gaurav

    2018-02-01

    The relaxation of a distorted black hole to its final state provides important tests of general relativity within the reach of current and upcoming gravitational wave facilities. In black hole perturbation theory, this phase consists of a simple linear superposition of exponentially damped sinusoids (the quasinormal modes) and of a power-law tail. How many quasinormal modes are necessary to describe waveforms with a prescribed precision? What error do we incur by only including quasinormal modes, and not tails? What other systematic effects are present in current state-of-the-art numerical waveforms? These issues, which are basic to testing fundamental physics with distorted black holes, have hardly been addressed in the literature. We use numerical relativity waveforms and accurate evolutions within black hole perturbation theory to provide some answers. We show that (i) a determination of the fundamental l =m =2 quasinormal frequencies and damping times to within 1% or better requires the inclusion of at least the first overtone, and preferably of the first two or three overtones; (ii) a determination of the black hole mass and spin with precision better than 1% requires the inclusion of at least two quasinormal modes for any given angular harmonic mode (ℓ , m ). We also improve on previous estimates and fits for the ringdown energy radiated in the various multipoles. These results are important to quantify theoretical (as opposed to instrumental) limits in parameter estimation accuracy and tests of general relativity allowed by ringdown measurements with high signal-to-noise ratio gravitational wave detectors.

  1. Astrophysical flows near [Formula: see text] gravity black holes.

    Science.gov (United States)

    Ahmed, Ayyesha K; Azreg-Aïnou, Mustapha; Bahamonde, Sebastian; Capozziello, Salvatore; Jamil, Mubasher

    In this paper, we study the accretion process for fluids flowing near a black hole in the context of f ( T ) teleparallel gravity. Specifically, by performing a dynamical analysis by a Hamiltonian system, we are able to find the sonic points. After that, we consider different isothermal test fluids in order to study the accretion process when they are falling onto the black hole. We find that these flows can be classified according to the equation of state and the black hole features. Results are compared in f ( T ) and f ( R ) gravity.

  2. Racial differences in sensitivity to behavioral integrity: attitudinal consequences, in-group effects, and "trickle down" among Black and non-Black employees.

    Science.gov (United States)

    Simons, Tony; Friedman, Ray; Liu, Leigh Anne; McLean Parks, Judi

    2007-05-01

    Recent research has suggested that employees are highly affected by perceptions of their managers' pattern of word-action consistency, which T. Simons (2002) called behavioral integrity (BI). The authors of the present study suggest that some employee racial groups may be more attentive to BI than others. They tested this notion using data from 1,944 employees working at 107 different hotels and found that Black employees rated their managers as demonstrating lower BI than did non-Black employees. Mediation analyses were consistent with the notion that these differences in perceived BI in turn account for cross-race differences in trust in management, interpersonal justice, commitment, satisfaction, and intent to stay. Results of hierarchical linear modeling were consistent with the idea that middle managers' perceptions of their senior managers' BI "trickle down" to affect line employee perceptions of the middle managers and that this trickle-down effect is stronger for Black employees. The authors interpret these results as indicative of heightened sensitivity to managers' BI on the part of Black employees. They also found a reverse in-group effect, in that Black employees were substantially more critical of Black managers than were non-Black employees. 2007 APA, all rights reserved

  3. Teste de envelhecimento precoce para sementes de azevém, aveia preta e milheto Accelerated aging test for ryegrass black oat grass and pearl millet seeds

    Directory of Open Access Journals (Sweden)

    Danton Camacho Garcia

    1999-06-01

    Full Text Available A viabilidade da aplicação e da padronização do teste de envelhecimento precoce em sementes de azevém, aveia preta e milheto foi verificada em três lotes, para cada espécie, com valores iniciais de germinação semelhantes. As sementes de cada lote foram submetidas ao teste por períodos de 24, 48, 72, 96 e 120 horas, à temperatura de 41°C e 100% de umidade relativa do ar. Em aveia preta, o período de 24 horas estratifica lotes de sementes pelo vigor. Para milheto e azevém, o período de envelhecimento para estratificar lotes de sementes pelo vigor pode ser de 24 a 48 horas. Períodos de 72 a 120 horas são muito drásticos para as três espécies e impedem a estratificação de lotes de sementes pelo vigor.Accelerated aging test standardization for seeds of ryegrass, black oat grass and pearl millet was cheked in three lots, of each specie, with similar initial values of germination. The seeds of each lot were submited to periods of 24, 48, 96 and 120 hours of temperature of 41°C and air relative humidity of 100%. In black oat grass the 24h period stratifies seed vigor among lots. However, for pearl millet and ryegrass the period can be of 24 to 48h. Periods of 72 to 120 hours are very severe to the three species and prevent the seed vigor lots stratification.

  4. Distortion of Schwarzschild-anti-de Sitter black holes to black strings

    International Nuclear Information System (INIS)

    Tomimatsu, Akira

    2005-01-01

    Motivated by the existence of black holes with various topologies in four-dimensional spacetimes with a negative cosmological constant, we study axisymmetric static solutions describing any large distortions of Schwarzschild-anti-de Sitter black holes parametrized by the mass m. Under the approximation such that m is much larger than the anti-de Sitter radius, it is found that a cylindrically symmetric black string is obtained as a special limit of distorted spherical black holes. Such a prolonged distortion of the event horizon connecting a Schwarzschild-anti-de Sitter black hole to a black string is allowed without violating both the usual black hole thermodynamics and the hoop conjecture for the horizon circumference

  5. Synthesis and characterization of Ti-Si-C-N nanocomposite coatings prepared by a filtered vacuum arc method

    Energy Technology Data Exchange (ETDEWEB)

    Thangavel, Elangovan, E-mail: t.elangophy@gmail.com [Advanced Thin Film Research Group, Materials Processing Division, Korea Institute of Materials Science, Changwon 641-831 (Korea, Republic of); Center for Nano-Wear, Yonsei University, Seoul 120-749 (Korea, Republic of); Lee, Seunghun; Nam, Kee-Seok; Kim, Jong-Kuk [Advanced Thin Film Research Group, Materials Processing Division, Korea Institute of Materials Science, Changwon 641-831 (Korea, Republic of); Kim, Do-Geun, E-mail: dogeunkim@kims.re.kr [Advanced Thin Film Research Group, Materials Processing Division, Korea Institute of Materials Science, Changwon 641-831 (Korea, Republic of)

    2013-01-15

    Highlights: Black-Right-Pointing-Pointer Preparation method was used as filtered vacuum arc (FVA) deposition. Black-Right-Pointing-Pointer Ternary coating obtained by using single carbon source with TMS gas. Black-Right-Pointing-Pointer Detailed discussion of chemical nature for these coating by using XPS. - Abstract: Ti-Si-C-N nanocomposite coatings were synthesized by a filtered vacuum arc (FVA) technique. A metal organic precursor, tetramethylsilane (TMS), was used as a source for silicon and carbon to deposit the Ti-Si-C-N nanocomposite coating with a Ti cathode source. The chemical and microstructural properties of the as-deposited coatings were systematically investigated using X-ray photoelectron spectroscopy (XPS), X-ray diffraction (XRD), and transmission electron microscopy (TEM). Nanoindentation and scratch tests were carried out to evaluate the mechanical and adhesion properties of the coatings. From the XPS analysis, it was found that the Si content in the coating increased from 2 to 16 at.% as the TMS flow rate was increased from 5 to 20 sccm. The TEM analysis clearly demonstrated that the coatings were composed of crystalline TiCN along with amorphous Si{sub 3}N{sub 4} as a secondary phase. From the XRD results, it was found that the crystallite size of TiCN increased with increasing Si content. The microstructure and mechanical properties of the TiSiCN coatings prepared by this method exhibited strong dependencies on the silicon content. A maximum hardness of 49 GPa and a coefficient of friction of 0.17 were obtained for the film with a silicon content of 3 at.%.

  6. Testing the Black Hole No-hair Theorem with OJ287

    Czech Academy of Sciences Publication Activity Database

    Valtonen, M.J.; Mikkola, S.; Lehto, H.J.; Gopakumar, A.; Hudec, René; Poledníková, J.

    2011-01-01

    Roč. 742, č. 1 (2011), 22/1-22/12 ISSN 0004-637X R&D Projects: GA ČR GA205/08/1207 Grant - others:GA ČR(CZ) GA102/09/0997; GA MŠk(CZ) ME09027 Institutional research plan: CEZ:AV0Z10030501 Keywords : black hole physics * BL Lacertae objects Subject RIV: BN - Astronomy, Celestial Mechanics, Astrophysics Impact factor: 6.024, year: 2011

  7. Testing the black disk limit in $pp$ collisions at very high energy

    OpenAIRE

    Brogueira, P.; de Deus, J. Dias

    2011-01-01

    We use geometric scaling invariant quantities to measure the approach, or not, of the imaginary and real parts of the elastic scattering amplitude, to the black disk limit, in $pp$ collisions at very high energy.

  8. 40 CFR 1051.305 - How must I prepare and test my production-line vehicles or engines?

    Science.gov (United States)

    2010-07-01

    ... production-line vehicles or engines? 1051.305 Section 1051.305 Protection of Environment ENVIRONMENTAL PROTECTION AGENCY (CONTINUED) AIR POLLUTION CONTROLS CONTROL OF EMISSIONS FROM RECREATIONAL ENGINES AND VEHICLES Testing Production-Line Vehicles and Engines § 1051.305 How must I prepare and test my production...

  9. Low-mass black holes as the remnants of primordial black hole formation.

    Science.gov (United States)

    Greene, Jenny E

    2012-01-01

    Bridging the gap between the approximately ten solar mass 'stellar mass' black holes and the 'supermassive' black holes of millions to billions of solar masses are the elusive 'intermediate-mass' black holes. Their discovery is key to understanding whether supermassive black holes can grow from stellar-mass black holes or whether a more exotic process accelerated their growth soon after the Big Bang. Currently, tentative evidence suggests that the progenitors of supermassive black holes were formed as ∼10(4)-10(5) M(⊙) black holes via the direct collapse of gas. Ongoing searches for intermediate-mass black holes at galaxy centres will help shed light on this formation mechanism.

  10. Radiotracers in the Black Sea: A Tool for Marine Environmental Assessments

    International Nuclear Information System (INIS)

    Gulin, S.B.; Egorov, V.N.; Polikarpov, G.G.; Stokozov, N.A.; Mirzoeva, N.Yu.; Tereshenko, N.N.; Gulina, L.V.; Proskurnin, V.Yu.; Osvath, I.

    2011-01-01

    Owing to its geographical location, the Black Sea has been one of the marine basins most contaminated with artificial radioactivity. During the pre-Chernobyl period, the main source of radioactive contamination of the Black Sea was the global fallout from the atmospheric nuclear weapon tests, which peaked in 1962 before the 1963 Test Ban Treaty was signed between the main nuclear states. As maximum global fallout was observed within the 40-50 o N latitude band that runs exactly across the Black Sea, this semi enclosed water body received high levels of the fallout radionuclides derived from the atmospheric weapons testing. Being a closest marine body to the Chernobyl site, the Black Sea and its broad drainage areas have received substantial amounts of the long-lived artificial radionuclides, particularly 90 Sr, 137 Cs, and plutonium isotopes, released into the atmosphere from the damaged nuclear reactor and delivered with the air masses moving south- and westward from the accident area. Besides direct atmospheric deposition, the Black Sea received (and continues to receive) additional radioactive input by river runoff, particularly to its northwestern area from the Danube and Dnieper Rivers. Resulting from contribution of the above-mentioned sources of radioactive contamination of the Black Sea, the 90 Sr concentration in its water ranks second after the Irish Sea, and third after the Baltic Sea with respect to 137 Cs concentration in seawater. Overview of results. Extensive radioecological studies performed during the last decades have showed that post-Chernobyl evolution and levels of man-made radioactivity in the Black Sea were governed, except radioactive decay, by the large-scale oceanographic, biogeochemical and ecological processes, which control the self-cleaning of the Black Sea environments against the radioactive contamination: first of all the vertical water mixing, which dilutes the surface radionuclide concentrations, the loss through the Bosporus

  11. Nutraceutical Value of Black Cherry Prunus serotina Ehrh. Fruits: Antioxidant and Antihypertensive Properties

    Directory of Open Access Journals (Sweden)

    Francisco J. Luna-Vázquez

    2013-11-01

    Full Text Available In Mexico black cherry (Prunus serotina Ehrh. fruits are consumed fresh, dried or prepared in jam. Considering the evidence that has linked intake of fruits and vegetables rich in polyphenols to cardiovascular risk reduction, the aim of this study was to characterize the phenolic profile of black cherry fruits and to determine their antioxidant, vasorelaxant and antihypertensive effects. The proximate composition and mineral contents of these fruits were also assessed. Black cherry fruits possess a high content of phenolic compounds and display a significant antioxidant capacity. High-performance liquid chromatography/mass spectrometric analysis indicated that hyperoside, anthocyanins and chlorogenic acid were the main phenolic compounds found in these fruits. The black cherry aqueous extract elicited a concentration-dependent relaxation of aortic rings and induced a significant reduction on systolic blood pressure in L-NAME induced hypertensive rats after four weeks of treatment. Proximate analysis showed that black cherry fruits have high sugar, protein, and potassium contents. The results derived from this study indicate that black cherry fruits contain phenolic compounds which elicit significant antioxidant and antihypertensive effects. These findings suggest that these fruits might be considered as functional foods useful for the prevention and treatment of cardiovascular diseases.

  12. Spectrally selective paint coatings. Preparation and characterization

    Energy Technology Data Exchange (ETDEWEB)

    Crnjak Orel, Z.C.; Klanjsek Gunde, M. [National Institute of Chemistry, Hajdrihova 19, SI-1000 Ljubljana (Slovenia)

    2001-06-01

    Preparation and characterization of spectrally selective paint coating for photothermal solar energy conversion are discussed. The applied methods for preparation of paints with described measurements and calculations of black-pigmented coatings were reviewed. The article represents not only possible future applications but also past and current applications of spectrally selective paint coating which are used all over the world since the 1980s. Spectrally selective paint coatings based on combinations of two types of resins, various types of pigments and three types of silica, were prepared. The influence of pigment type and pigment volume concentration (PVC) was studied by applying the Kubelka-Munk (K-M) theory. The relation between the degrees of dispersion and distribution of pigment particles across the paint layer is discussed in terms of K-M coefficients.

  13. Electromagnetic field in higher-dimensional black-hole spacetimes

    International Nuclear Information System (INIS)

    Krtous, Pavel

    2007-01-01

    A special test electromagnetic field in the spacetime of the higher-dimensional generally rotating NUT-(anti-)de Sitter black hole is found. It is adjusted to the hidden symmetries of the background represented by the principal Killing-Yano tensor. Such an electromagnetic field generalizes the field of charged black hole in four dimensions. In higher dimensions, however, the gravitational backreaction of such a field cannot be consistently solved

  14. Reduced graphene oxide/hydroxylated styrene-butadiene-styrene tri-block copolymer electroconductive nanocomposites: Preparation and properties

    Energy Technology Data Exchange (ETDEWEB)

    Xiong, Yuanqin; Xie, Yanyan [Institute of Polymer Science and Engineering, College of Chemistry and Chemical Engineering, Hunan University, Changsha 410082 (China); Zhang, Fan [College of Chemistry and Chemical Engineering, Jishou University, Jishou 416000 (China); Ou, Encai; Jiang, Zhuojuan; Ke, Lili; Hu, Ding [Institute of Polymer Science and Engineering, College of Chemistry and Chemical Engineering, Hunan University, Changsha 410082 (China); Xu, Weijian, E-mail: weijianxu59@gmail.com [Institute of Polymer Science and Engineering, College of Chemistry and Chemical Engineering, Hunan University, Changsha 410082 (China)

    2012-08-20

    Highlights: Black-Right-Pointing-Pointer RGO/HO-SBS nanocomposites are prepared successfully. Black-Right-Pointing-Pointer The introduction of -OH improves the compatibility between RGO and HO-SBS. Black-Right-Pointing-Pointer RGO disperse homogeneously and form a compact continuous network in matrix (HO-SBS). Black-Right-Pointing-Pointer The percolation threshold of the nanocomposites is of 0.2-0.5 wt% (0.09-0.23 vol%) and its conductivity is up to 1.3 S/m. - Abstract: Flexible and electroconductive nanocomposites based on reduced graphene oxide (RGO) and hydroxylated styrene-butadiene-styrene tri-block copolymer (HO-SBS) were prepared by solution blending method. By the introduction of the groups of -OH and >C=O onto SBS, the compatibility between RGO and SBS was enhanced. Field emission scanning electron microscopy (FE-SEM) and high-resolution transmission electron microscopy (HR-TEM) showed that RGO dispersed homogeneously and formed a compact continuous network in matrix (HO-SBS). The addition of RGO improved the thermal stability of the RGO/HO-SBS nanocomposites while slightly lowered the mechanical property. Moreover, RGO gave the nanocomposites a maximum electrical conductivity up to 1.3 S/m.

  15. Changes in the Quality of Black Mulberry and Blueberry Sherbets During Storage

    Directory of Open Access Journals (Sweden)

    Ahsen Rayman Ergün

    2017-01-01

    Full Text Available This study was evaluated the quality properties of traditional drink sherbets that are prepared from black mulberry and blueberry fruits. After production sherbets were investigated to determine their pH, acidity, °brix and colour values, total sugar, phenolic, anthocyanin and antioxidant contents. Moreover the sherbets stored at 4°C during 2 months and the changes in these quality properties were examined per month. As a result statistically significant changes were observed in the quality properties of these sherbets of black mulberry and blueberry fruits which are known with their rich content of phytochemical compounds. The results show that in blueberry sherbet the degradation of phenolics was faster than black mulberry sherbet. Anthocyanins that are higher in black mulberry sherbets after production were preserved better in blueberry sherbets at the end of 2nd month. L*and a* values decreased for blackberry and blueberry sherbets during storage. b* value decreased from 5.59 to 4.92 for blackberry sherbet while it increased from 0.62 to 0.79 for blueberry sherbet at the end of the storage time.

  16. Black/white hole radiation from dispersive theories

    International Nuclear Information System (INIS)

    Macher, Jean; Parentani, Renaud

    2009-01-01

    We study the fluxes emitted by black holes when using dispersive field theories. We work with stationary one-dimensional backgrounds which are asymptotically flat on both sides of the horizon. The asymptotic fluxes are governed by a 3x3 Bogoliubov transformation. The fluxes emitted by the corresponding white holes are regular and governed by the inverse transformation. We numerically compute the spectral properties of these fluxes for both sub- and superluminal quartic dispersion. The leading deviations with respect to the dispersionless flux are computed and shown to be governed by a critical frequency above which there is no radiation. Unlike the UV scale governing dispersion, its value critically depends on the asymptotic properties of the background. We also study the flux outside the robust regime. In particular we show that its low-frequency part remains almost thermal but with a temperature which significantly differs from the standard one. Applications to four-dimensional black holes and Bose-Einstein condensates are in preparation.

  17. Analogue Hawking radiation from astrophysical black-hole accretion

    International Nuclear Information System (INIS)

    Das, Tapas K

    2004-01-01

    We show that spherical accretion onto astrophysical black holes can be considered as a natural example of an analogue system. We provide, for the first time, an exact analytical scheme for calculating the analogue Hawking temperature and surface gravity for general relativistic accretion onto astrophysical black holes. Our calculation may bridge the gap between the theory of transonic astrophysical accretion and the theory of analogue Hawking radiation. We show that the domination of the analogue Hawking temperature over the actual Hawking temperature may be a real astrophysical phenomenon, though observational tests of this fact will at best be difficult and at worst might prove to be impossible. We also discuss the possibilities of the emergence of analogue white holes around astrophysical black holes. Our calculation is general enough to accommodate accreting black holes with any mass

  18. Black Culture

    Directory of Open Access Journals (Sweden)

    Angela Khristin Brown

    2013-07-01

    Full Text Available The migration of blacks in North America through slavery became united.  The population of blacks past downs a tradition of artist through art to native born citizens. The art tradition involved telling stories to each generation in black families. The black culture elevated by tradition created hope to determine their personal freedom to escape from poverty of enslavement and to establish a way of life through tradition. A way of personal freedoms was through getting a good education that lead to a better foundation and a better way of life.

  19. Tidal Forces in Dyonic Reissner-Nördstrom Black Hole

    Science.gov (United States)

    Sharif, M.; Kousar, Lubna

    2018-03-01

    This paper investigates the tidal as well as magnetic charge effects produced in dyonic Reissner-Nordström black hole. We evaluate Newtonian radial acceleration using radial geodesics for freely falling test particles. We establish system of equations governing radial and angular tidal forces using geodesic deviation equation and discuss their solutions for bodies falling freely towards this black hole. The radial tidal force turns out to be compressing outside the event horizon whereas the angular tidal force changes sign between event and Cauchy horizons unlike Schwarzschild black hole. The radial geodesic component starts decreasing in dyonic Reissner-Nordström black hole unlike Schwarzschild case. We conclude that magnetic charge strongly affects the radial as well as angular components of tidal force.

  20. Magnetized black holes and black rings in the higher dimensional dilaton gravity

    International Nuclear Information System (INIS)

    Yazadjiev, Stoytcho S.

    2006-01-01

    In this paper we consider magnetized black holes and black rings in the higher dimensional dilaton gravity. Our study is based on exact solutions generated by applying a Harrison transformation to known asymptotically flat black hole and black ring solutions in higher dimensional spacetimes. The explicit solutions include the magnetized version of the higher dimensional Schwarzschild-Tangherlini black holes, Myers-Perry black holes, and five-dimensional (dipole) black rings. The basic physical quantities of the magnetized objects are calculated. We also discuss some properties of the solutions and their thermodynamics. The ultrarelativistic limits of the magnetized solutions are briefly discussed and an explicit example is given for the D-dimensional magnetized Schwarzschild-Tangherlini black holes

  1. Resilient modulus of black cotton soil

    Directory of Open Access Journals (Sweden)

    K.H. Mamatha

    2017-03-01

    Full Text Available Resilient modulus (MR values of pavement layers are the basic input parameters for the design of pavements with multiple layers in the current mechanistic empirical pavement design guidelines. As the laboratory determination of resilient modulus is costly, time consuming and cumbersome, several empirical models are developed for the prediction of resilient modulus for different regions of the world based on the database of resilient modulus values of local soils. For use of these relationships there is a need to verify the suitability of these models for local conditions. Expansive clay called black cotton soil (BC soil is found in several parts of India and is characterized by low strength and high compressibility. This soil shows swell – shrink behaviour upon wetting and drying and are problematic. The BC soil shows collapse behaviour on soaking and therefore the strength of the soil needs to be improved. Additive stabilization is found to be very effective in stabilizing black cotton soils and generally lime is used to improve the strength and durability of the black cotton soil. In this paper, the results of repeated load tests on black cotton soil samples for the determination of MR under soaked and unsoaked conditions at a relative compaction levels of 100% and 95% of both standard and modified proctor conditions are reported. The results indicate that the black cotton soil fails to meet the density requirement of the subgrade soil and shows collapse behaviour under soaked condition. To overcome this, lime is added as an additive to improve the strength of black cotton soil and repeated load tests were performed as per AASHTO T 307 - 99 for MR determination. The results have shown that the samples are stable under modified proctor condition with MR values ranging from 36 MPa to 388 MPa for a lime content of 2.5% and curing period ranging from 7 to 28 days. Also, it is observed that, the CBR based resilient modulus is not in agreement

  2. Study On The Uranium Adsorption Capability Of Bone Black In Radioactive Waste Water Treatment

    International Nuclear Information System (INIS)

    Phan Dinh Tuan

    2008-01-01

    It has been found that bone black can adsorb uranium and radium from radioactive wastewater. Nevertheless, bone black is not so competitive for the low adsorption capability and the slow adsorption rate. The article describes the research results in increasing the uranium adsorption capability of bone black by treating it with hydrochloric acid. The influences of pH on adsorption capability and the results of batch- and column tests have been investigated. Column tests for elution process have pointed out that HCl is quite good eluent for uranium. It is recommended to apply the treated bone black for radioactive wastewater treatment and uranium recovery. (author)

  3. Optimization of the Surface Structure on Black Silicon for Surface Passivation.

    Science.gov (United States)

    Jia, Xiaojie; Zhou, Chunlan; Wang, Wenjing

    2017-12-01

    Black silicon shows excellent anti-reflection and thus is extremely useful for photovoltaic applications. However, its high surface recombination velocity limits the efficiency of solar cells. In this paper, the effective minority carrier lifetime of black silicon is improved by optimizing metal-catalyzed chemical etching (MCCE) method, using an Al 2 O 3 thin film deposited by atomic layer deposition (ALD) as a passivation layer. Using the spray method to eliminate the impact on the rear side, single-side black silicon was obtained on n-type solar grade silicon wafers. Post-etch treatment with NH 4 OH/H 2 O 2 /H 2 O mixed solution not only smoothes the surface but also increases the effective minority lifetime from 161 μs of as-prepared wafer to 333 μs after cleaning. Moreover, adding illumination during the etching process results in an improvement in both the numerical value and the uniformity of the effective minority carrier lifetime.

  4. Satellite monitoring of black bear.

    Science.gov (United States)

    Craighead, J. J.; Craighead, F. C., Jr.; Varney, J. R.; Cote, C. E.

    1971-01-01

    Description of a feasibility experiment recently performed to test the use of a satellite system for telemetering environmental and physiological data from the winter den of a 'hibernating' black bear, Ursus americanus. The instrumentation procedure and evaluations of the equipment performance and sensory data obtained are discussed in detail.

  5. The Black Lives Matter Movement and Historically Black Colleges and Universities

    Science.gov (United States)

    Gasman, Marybeth

    2017-01-01

    This article looks at the Black Lives Matter Movement and Historically Black Colleges and Universities. Historically Black Colleges and Universities (HBCUs) continue to play an important role in society. However, what the Black Lives Matter movement shows consistently is that predominantly White institutions need to change, to step up and embrace…

  6. Innermost stable circular orbit of Kerr-MOG black hole

    Energy Technology Data Exchange (ETDEWEB)

    Lee, Hyun-Chul; Han, Yong-Jin [Soonchunhyang University, Department of Physics, Asan (Korea, Republic of)

    2017-10-15

    We study the innermost stable circular orbit (ISCO) of the metric of the Kerr black hole in modified gravity (Kerr-MOG black hole), which is one of the exact solutions of the field equation of modified gravity in the strong gravity regime. The Kerr-MOG metric is constructed; it is the commonly known Kerr metric in Boyer-Lindquist coordinates by adding a repulsive term like the Yukawa force, which is explained in quantum gravity. In this paper, we numerically calculate the circular orbit of a photon and the ISCO of a test particle of Kerr-MOG black holes. (orig.)

  7. School age test or procedure preparation

    Science.gov (United States)

    ... your child with books, bubbles, games, hand-held video games, or other activities. PLAY PREPARATION Children often avoid ... using this type of communication. Older children may benefit from videos that show children of the same age explaining, ...

  8. Preparation results for lifetime test of conversion LEU fuel in plutonium production reactors

    International Nuclear Information System (INIS)

    Vatulin, A.; Stetskiy, Yu.; Kukharkin, N.; Kalougin, A.; Gavrilov, P.; Ivanov, A.

    1999-01-01

    The program of converting Russian production reactors for the purpose to stop their plutonium fabrication is currently in progress. The program also provides for operation of these reactors under the conversion mode with using of low-enriched fuel (LEU). LEU fuel elements were developed and activities related to their preparation for reactor tests were carried out. (author)

  9. Metabolism and prebiotics activity of anthocyanins from black rice (Oryza sativa L.) in vitro.

    Science.gov (United States)

    Zhu, Yongsheng; Sun, Hanju; He, Shudong; Lou, Qiuyan; Yu, Min; Tang, Mingming; Tu, Lijun

    2018-01-01

    Anthocyanins are naturally active substances. In this study, anthocyanins from black rice were obtained by membrane filtration and column chromatography separation. Five anthocyanin monomers in black rice extract were identified by HPLC-MS/MS, and the major anthocyanin monomer (cyanidin-3-glucoside, C3G) was purified by preparative HPLC (Pre-HPLC). The proliferative effects of the anthocyanins on Bifidobacteria and Lactobacillus were investigated by determining the media pH, bacterial populations and metabolic products. After anaerobic incubation at 37 °C for 48 h, not only the pH of the media containing C3G was lower than that of the extract of black rice anthocyanin (BRAE), but the numbers of both Bifidobacteria and Lactobacillus were also significantly increased. Furthermore, hydroxyphenylpropionic, hydroxyphenylacetic, and hydroxybenzoic acids and other metabolites were detected by GC-MS in vitro. Our results revealed that the anthocyanins and anthocyanin monomers from black rice had prebiotic activity and they were metabolized into several small molecules by Bifidobacteria and Lactobacillus.

  10. Testing the relativistic Doppler boost hypothesis for supermassive black hole binary candidates

    Science.gov (United States)

    Charisi, Maria; Haiman, Zoltán; Schiminovich, David; D'Orazio, Daniel J.

    2018-06-01

    Supermassive black hole binaries (SMBHBs) should be common in galactic nuclei as a result of frequent galaxy mergers. Recently, a large sample of sub-parsec SMBHB candidates was identified as bright periodically variable quasars in optical surveys. If the observed periodicity corresponds to the redshifted binary orbital period, the inferred orbital velocities are relativistic (v/c ≈ 0.1). The optical and ultraviolet (UV) luminosities are expected to arise from gas bound to the individual BHs, and would be modulated by the relativistic Doppler effect. The optical and UV light curves should vary in tandem with relative amplitudes which depend on the respective spectral slopes. We constructed a control sample of 42 quasars with aperiodic variability, to test whether this Doppler colour signature can be distinguished from intrinsic chromatic variability. We found that the Doppler signature can arise by chance in ˜20 per cent (˜37 per cent) of quasars in the nUV (fUV) band. These probabilities reflect the limited quality of the control sample and represent upper limits on how frequently quasars mimic the Doppler brightness+colour variations. We performed separate tests on the periodic quasar candidates, and found that for the majority, the Doppler boost hypothesis requires an unusually steep UV spectrum or an unexpectedly large BH mass and orbital velocity. We conclude that at most approximately one-third of these periodic candidates can harbor Doppler-modulated SMBHBs.

  11. Black hole versus cosmological horizon entropy

    International Nuclear Information System (INIS)

    Davis, Tamara M; Davies, P C W; Lineweaver, Charles H

    2003-01-01

    The generalized second law of thermodynamics states that entropy always increases when all event horizons are attributed with an entropy proportional to their area. We test the generalized second law by investigating the change in entropy when dust, radiation and black holes cross a cosmological event horizon. We generalize for flat, open and closed Friedmann-Robertson-Walker universes by using numerical calculations to determine the cosmological horizon evolution. In most cases, the loss of entropy from within the cosmological horizon is more than balanced by an increase in cosmological event horizon entropy, maintaining the validity of the generalized second law of thermodynamics. However, an intriguing set of open universe models shows an apparent entropy decrease when black holes disappear over the cosmological event horizon. We anticipate that this apparent violation of the generalized second law will disappear when solutions are available for black holes embedded in arbitrary backgrounds

  12. Black hole levitron

    International Nuclear Information System (INIS)

    Arsiwalla, Xerxes D.; Verlinde, Erik P.

    2010-01-01

    We study the problem of spatially stabilizing four dimensional extremal black holes in background electric/magnetic fields. Whilst looking for stationary stable solutions describing black holes placed in external fields we find that taking a continuum limit of Denef et al.'s multicenter supersymmetric black hole solutions provides a supergravity description of such backgrounds within which a black hole can be trapped within a confined volume. This construction is realized by solving for a levitating black hole over a magnetic dipole base. We comment on how such a construction is akin to a mechanical levitron.

  13. [The principle of registration, evaluation and testing of disinfecting preparations].

    Science.gov (United States)

    Röhm-Rodowald, Ewa; Jakimiak, Bozenna; Podgórska, Marta

    2008-01-01

    Disinfectants are used to produce a state in which the number of living micro-organisms has been reduced to a level which is appropriate to the practical situation. For any products which are included in the Biocidal Directive 98/8/EC, for which specific activity is claimed, test data has to be approved by the regulatory authority and a product license obtained before the product can be offered for sale. Disinfectants can be recorded as biocidal products or medical devices. Presently, it is possible to measure the activity of a product on defined micro-organisms in specified experimental conditions. Efficacy is the result of the use of a product according to a defined application. To allow different requirements in different areas of application, separate tests and pass criteria have been or will be prepared for each of following three areas of application: medical, veterinary and group comprising food, industrial, domestic and institutional areas. The laboratory methods to be used for testing the activity of chemical disinfectants meets the European standards. The tests are categorised on a modular basis as follows: phase 1 tests, phase 2 step 1 tests, phase 2 step 2 tests and phase 3 tests. In order to claim that a product has disinfectant properties, suitable for use in the medical area, the product shall be tested according to European standards: phase 2 step 1 tests, phase 2 step 2 tests. Phase 1 tests are not required to support claims for chemical disinfectants used in human medicine. Only phase 1 tests are required to support claims for active substances for which no particular area of application is specified. Medical devices are subjects to the European Directive 93/42/EEC which requires that a product must carry a CE mark. Disinfectants which are intended specifically by its manufacturer to be used on medical devices are themselves medical devices and so these products, as well as conforming to the instrument disinfection European standards as specified

  14. Black Holes

    OpenAIRE

    Horowitz, Gary T.; Teukolsky, Saul A.

    1998-01-01

    Black holes are among the most intriguing objects in modern physics. Their influence ranges from powering quasars and other active galactic nuclei, to providing key insights into quantum gravity. We review the observational evidence for black holes, and briefly discuss some of their properties. We also describe some recent developments involving cosmic censorship and the statistical origin of black hole entropy.

  15. Contemporary genetic structure and postglacial demographic history of the black scorpionfish, Scorpaena porcus, in the Mediterranean and the Black Seas.

    Science.gov (United States)

    Boissin, E; Micu, D; Janczyszyn-Le Goff, M; Neglia, V; Bat, L; Todorova, V; Panayotova, M; Kruschel, C; Macic, V; Milchakova, N; Keskin, Ç; Anastasopoulou, A; Nasto, I; Zane, L; Planes, S

    2016-05-01

    Understanding the distribution of genetic diversity in the light of past demographic events linked with climatic shifts will help to forecast evolutionary trajectories of ecosystems within the current context of climate change. In this study, mitochondrial sequences and microsatellite loci were analysed using traditional population genetic approaches together with Bayesian dating and the more recent approximate Bayesian computation scenario testing. The genetic structure and demographic history of a commercial fish, the black scorpionfish, Scorpaena porcus, was investigated throughout the Mediterranean and Black Seas. The results suggest that the species recently underwent population expansions, in both seas, likely concomitant with the warming period following the Last Glacial Maximum, 20 000 years ago. A weak contemporaneous genetic differentiation was identified between the Black Sea and the Mediterranean Sea. However, the genetic diversity was similar for populations of the two seas, suggesting a high number of colonizers entered the Black Sea during the interglacial period and/or the presence of a refugial population in the Black Sea during the glacial period. Finally, within seas, an east/west genetic differentiation in the Adriatic seems to prevail, whereas the Black Sea does not show any structured spatial genetic pattern of its population. Overall, these results suggest that the Black Sea is not that isolated from the Mediterranean, and both seas revealed similar evolutionary patterns related to climate change and changes in sea level. © 2016 John Wiley & Sons Ltd.

  16. Search for black holes

    International Nuclear Information System (INIS)

    Cherepashchuk, Anatolii M

    2003-01-01

    Methods and results of searching for stellar mass black holes in binary systems and for supermassive black holes in galactic nuclei of different types are described. As of now (June 2002), a total of 100 black hole candidates are known. All the necessary conditions Einstein's General Relativity imposes on the observational properties of black holes are satisfied for candidate objects available, thus further assuring the existence of black holes in the Universe. Prospects for obtaining sufficient criteria for reliably distinguishing candidate black holes from real black holes are discussed. (reviews of topical problems)

  17. The influence of paint dispersion parameters on the spectral selectivity of black-pigmented coatings

    Energy Technology Data Exchange (ETDEWEB)

    Gunde, M.K.; Orel, Z.C. [National Institute of Chemistry, Ljubljana (Slovenia); Hutchins, M.G. [Oxford Brookes University, Oxford (United Kingdom). School of Engineering

    2003-10-31

    The optical properties of variously prepared black-pigmented solar absorbing paints were calculated in terms of their effective absorption and scattering abilities. The phenomenological two-parameter Kubelka-Munk effective medium theory was applied. Paints with the same composition were prepared for different degrees of pigment dispersion and characterized by the average size of pigment agglomerates present in the pigment/vehicle system. Prepared paints were applied to aluminium foil in two ways, by coil coating and by spraying. The size of coarse pigment particles and the paint application technique influence the spectral selectivity and thus determine the final performance of spectrally selective surfaces. (author)

  18. Black Holes and Large Order Quantum Geometry

    CERN Document Server

    Huang, Min-xin; Mariño, Marcos; Tavanfar, Alireza

    2009-01-01

    We study five-dimensional black holes obtained by compactifying M theory on Calabi-Yau threefolds. Recent progress in solving topological string theory on compact, one-parameter models allows us to test numerically various conjectures about these black holes. We give convincing evidence that a microscopic description based on Gopakumar-Vafa invariants accounts correctly for their macroscopic entropy, and we check that highly nontrivial cancellations -which seem necessary to resolve the so-called entropy enigma in the OSV conjecture- do in fact occur. We also study analytically small 5d black holes obtained by wrapping M2 branes in the fiber of K3 fibrations. By using heterotic/type II duality we obtain exact formulae for the microscopic degeneracies in various geometries, and we compute their asymptotic expansion for large charges.

  19. Noncommutative black holes

    Energy Technology Data Exchange (ETDEWEB)

    Lopez-DomInguez, J C [Instituto de Fisica de la Universidad de Guanajuato PO Box E-143, 37150 Leoen Gto. (Mexico); Obregon, O [Instituto de Fisica de la Universidad de Guanajuato PO Box E-143, 37150 Leoen Gto. (Mexico); RamIrez, C [Facultad de Ciencias FIsico Matematicas, Universidad Autonoma de Puebla, PO Box 1364, 72000 Puebla (Mexico); Sabido, M [Instituto de Fisica de la Universidad de Guanajuato PO Box E-143, 37150 Leoen Gto. (Mexico)

    2007-11-15

    We study noncommutative black holes, by using a diffeomorphism between the Schwarzschild black hole and the Kantowski-Sachs cosmological model, which is generalized to noncommutative minisuperspace. Through the use of the Feynman-Hibbs procedure we are able to study the thermodynamics of the black hole, in particular, we calculate Hawking's temperature and entropy for the 'noncommutative' Schwarzschild black hole.

  20. Standard practice for preparing, cleaning, and evaluating corrosion test specimens

    CERN Document Server

    American Society for Testing and Materials. Philadelphia

    2003-01-01

    1.1 This practice covers suggested procedures for preparing bare, solid metal specimens for tests, for removing corrosion products after the test has been completed, and for evaluating the corrosion damage that has occurred. Emphasis is placed on procedures related to the evaluation of corrosion by mass loss and pitting measurements. (Warning—In many cases the corrosion product on the reactive metals titanium and zirconium is a hard and tightly bonded oxide that defies removal by chemical or ordinary mechanical means. In many such cases, corrosion rates are established by mass gain rather than mass loss.) 1.2 This standard does not purport to address all of the safety concerns, if any, associated with its use. It is the responsibility of the user of this standard to establish appropriate safety and health practices and determine the applicability of regulatory limitations prior to use. For specific precautionary statements, see 1 and 7.2.

  1. Preparation of ZnO/SiO{sub 2} gel composites and their performance of H{sub 2}S removal at room temperature

    Energy Technology Data Exchange (ETDEWEB)

    Liu, Guoqiang [Laboratory of Advanced Materials, Department of Materials Science and Engineering, Tsinghua University, Beijing 100084 (China); Huang, Zheng-Hong, E-mail: zhhuang@tsinghua.edu.cn [Laboratory of Advanced Materials, Department of Materials Science and Engineering, Tsinghua University, Beijing 100084 (China); Kang, Feiyu [Laboratory of Advanced Materials, Department of Materials Science and Engineering, Tsinghua University, Beijing 100084 (China); Institute of Advanced Materials Research, Graduate School at Shenzhen, Tsinghua University, Shenzhen 518055 (China)

    2012-05-15

    Graphical abstract: The ZnO/SiO{sub 2} gel composites exhibit mixed type isotherms, in which the initial part is type I, and intermediate and high relative pressures are type IV with a hysteresis loop of type H2. The breakthrough time of ZnO/SiO{sub 2} composites first increased sharply up to 400 Degree-Sign C with the H{sub 2}S breakthrough capacity is up to 96.4 mg/g, and then decrease dramatically with further rising of temperature beyond 500 Degree-Sign C. Highlights: Black-Right-Pointing-Pointer High surface area ZnO/SiO{sub 2} gel composites were prepared by co-sol-gel method. Black-Right-Pointing-Pointer The active phase (ZnO) well disperses in the composites. Black-Right-Pointing-Pointer The highest H{sub 2}S adsorption capacity of the composites reaches up to 96.4 mg/g. Black-Right-Pointing-Pointer Both physisorption and the active phase reactivation governed the H{sub 2}S removal process. - Abstract: ZnO/SiO{sub 2} gel composites with different active component loading were prepared by sol-gel method combined with ambient drying process, followed by thermal treatment. The gel composites were characterized by scanning electron microscopy (SEM), nitrogen adsorption, X-ray diffraction (XRD), FTIR and X-ray photoelectron spectroscopy (XPS), and their performances for H{sub 2}S removal were evaluated by dynamic testing at room temperature. The as prepared materials exhibited high surface area with multimodal pore size distributions in micropore and mesopore region. The porous properties were significantly influenced both by the ZnO loading ratio and the treated temperature. The gel composites showed a high performance for H{sub 2}S removal, with the highest H{sub 2}S adsorption capacity of 96.4 mg/g for the sample treated at 400 Degree-Sign C with 30 wt% ZnO. Both physisorption and the active phase reactivation governed the H{sub 2}S removal process. It needs to optimize the composites' porous structure and active component loading amount.

  2. Performance of Ceriporiopsis sp. in the Treatment of Black Liquor Wastewater

    OpenAIRE

    Sari, Ajeng Arum

    2016-01-01

    High amounts of black liquor wastewater are generated from bioethanol production by using oil palm empty fruit bunches. It contains an alkaline solution (NaOH), so it is quite toxic for aquatic ecosystems if discharged directly into waters. Black liquor has been treated by coagulation method, and it still needs additional treatment. This study aimed to determine degradation of black liquor wastewater by selected white-rot fungi (WRF). Five different strains of WRF have been tested for their a...

  3. Preparation and luminescence properties of Eu{sup 2+}doped {gamma}-aluminum oxynitride transparent ceramics

    Energy Technology Data Exchange (ETDEWEB)

    Zhang, Fang; Yuan, Xianyuan; Wang, Shaohua [Shanghai Institute of Ceramics, Chinese Academy of Sciences, 1295 Dingxi Road, Shanghai (China); Wang, Shiwei, E-mail: swwang51@mail.sic.ac.cn [Shanghai Institute of Ceramics, Chinese Academy of Sciences, 1295 Dingxi Road, Shanghai (China)

    2013-01-15

    Eu{sup 2+} doped {gamma}-AlON transparent ceramics have been prepared by the solid-state reaction sintering method. The influences of Eu concentration on both strength, transparency and luminescence properties of the as-prepared samples were discussed. The strength and transparency decreased as Eu content increased. Two bands were observed in the emission spectrum of each sample. One (B{sub 1}) was narrow and centered at around 401 nm, the other (B{sub 2}) was comparatively broader, and the location of its center as well as the intensity ratio of peak values of B{sub 2} to that of B{sub 1} varied with Eu content. - Highlights: Black-Right-Pointing-Pointer Eu{sub 2}O{sub 3} was an effective sintering aid in fabrication of transparent {gamma}-AlON ceramics. Black-Right-Pointing-Pointer Eu-doped transparent {gamma}-AlON ceramics exhibited broad emission spectra composed of two bands. Black-Right-Pointing-Pointer The relationship between crystal position of Eu{sup 2+} ions and luminescent properties was given.

  4. Black branes and black strings in the astrophysical and cosmological context

    Science.gov (United States)

    Akarsu, Özgür; Chopovsky, Alexey; Zhuk, Alexander

    2018-03-01

    We consider Kaluza-Klein models where internal spaces are compact flat or curved Einstein spaces. This background is perturbed by a compact gravitating body with the dust-like equation of state (EoS) in the external/our space and an arbitrary EoS parameter Ω in the internal space. Without imposing any restrictions on the form of the perturbed metric and the distribution of the perturbed energy densities, we perform the general analysis of the Einstein and conservation equations in the weak-field limit. All conclusions follow from this analysis. For example, we demonstrate that the perturbed model is static and perturbed metric preserves the block-diagonal form. In a particular case Ω = - 1 / 2, the found solution corresponds to the weak-field limit of the black strings/branes. The black strings/branes are compact gravitating objects which have the topology (four-dimensional Schwarzschild spacetime) × (d-dimensional internal space) with d ≥ 1. We present the arguments in favour of these objects. First, they satisfy the gravitational tests for the parameterized post-Newtonian parameter γ at the same level of accuracy as General Relativity. Second, they are preferable from the thermodynamical point of view. Third, averaging over the Universe, they do not destroy the stabilization of the internal space. These are the astrophysical and cosmological aspects of the black strings/branes.

  5. Redshift anisotropy among test-particle sources inside a black hole

    International Nuclear Information System (INIS)

    Debney, G.

    1976-01-01

    An elementary (mass-normalized) model of observers and emitters of light in free-fall within a black hole's radius is investigated in terms of the redshift spectrum induced. All observers and emitters follow the same kinds of trajectories, radially inward and starting from rest at spatial infinity. The major results are concerned with demonstrating the types of redshifts possible in all directions on a typical observer's celestial sphere. These are simulated by considering all equatorial light paths inside and generalizing to three dimensions by symmetry. Under certain assumptions a direction for maximum redshift and one for minimum redshift are obtained; these lie on antipodal points on the observer's celestial sphere. No multiple imaging or focusing is possible from isotropic sources inside r = 2m, however. At this stage no luminosity distances or intensity results are developed; these more complicated relationships would be required to simulate the actual picture getting through to an observer. Some of the redshift results are applied to a black hole whose scale is cosmological. This extreme example is included mainly as a curiosity to illustrate the impact of a simple change of scale and to reemphasize the importance of the microwave isotropy to theoretical models. A careful analytical formulation of general relativistic redshifts as seen in local Lorentz frames provides the tools for this investigation. (author)

  6. Redshift anisotropy among test-particle sources inside a black hole

    Energy Technology Data Exchange (ETDEWEB)

    Debney, G [Virginia Polytechnic Inst. and State Univ., Blacksburg (USA)

    1976-09-01

    An elementary (mass-normalized) model of observers and emitters of light in free-fall within a black hole's radius is investigated in terms of the redshift spectrum induced. All observers and emitters follow the same kinds of trajectories, radially inward and starting from rest at spatial infinity. The major results are concerned with demonstrating the types of redshifts possible in all directions on a typical observer's celestial sphere. These are simulated by considering all equatorial light paths inside and generalizing to three dimensions by symmetry. Under certain assumptions a direction for maximum redshift and one for minimum redshift are obtained; these lie on antipodal points on the observer's celestial sphere. No multiple imaging or focusing is possible from isotropic sources inside r = 2m, however. At this stage no luminosity distances or intensity results are developed; these more complicated relationships would be required to simulate the actual picture getting through to an observer. Some of the redshift results are applied to a black hole whose scale is cosmological. This extreme example is included mainly as a curiosity to illustrate the impact of a simple change of scale and to reemphasize the importance of the microwave isotropy to theoretical models. A careful analytical formulation of general relativistic redshifts as seen in local Lorentz frames provides the tools for this investigation.

  7. Black hole critical phenomena without black holes

    Indian Academy of Sciences (India)

    large values of Ф, black holes do form and for small values the scalar field ... on the near side of the ridge ultimately evolve to form black holes while those configu- ... The inset shows a bird's eye view looking down on the saddle point.

  8. “How It’s Done”: The Role of Mentoring and Advice in Preparing the Next Generation of Historically Black College and University Presidents

    Directory of Open Access Journals (Sweden)

    Felecia Commodore

    2016-06-01

    Full Text Available The college and university presidency is one of the most coveted positions in academe. Due to the projected retirements of current Historically Black College and University (HBCU presidents, the researchers interviewed 21 current presidents, institutional board members, and presidential search firm personnel to explore what current HBCU leadership identifies as important mentoring/mentee practices, mentoring/mentee opportunities, and professional advice for HBCU presidential aspirants to consider. The findings, based on the coding and analysis of semi-structured qualitative interviews, revealed that self-awareness, focusing on the essential aspects of the job and not merely the perks, openness to being mentored and willingness to shadow a successful leader, experience in serving in various administrative capacities, participating in professional leadership development activities, earning of a terminal degree, displaying humility, understanding academic politics, and learning how to present oneself as an executive is important in the preparation of a leader of an HBCU.

  9. Black widow spider

    Science.gov (United States)

    ... medlineplus.gov/ency/article/002858.htm Black widow spider To use the sharing features on this page, please enable JavaScript. The black widow spider (Latrodectus) has a shiny black body with a ...

  10. White dwarfs - black holes. Weisse Zwerge - schwarze Loecher

    Energy Technology Data Exchange (ETDEWEB)

    Sexl, R; Sexl, H

    1975-04-01

    The physical arguments and problems of relativistic astrophysics are presented in a correct way, but without any higher mathematics. The book is addressed to teachers, experimental physicists, and others with a basic knowledge covering an introductory lecture in physics. The issues dealt with are: fundamentals of general relativity, classical tests of general relativity, curved space-time, stars and planets, pulsars, gravitational collapse and black holes, the search for black holes, gravitational waves, cosmology, cosmogony, and the early universe.

  11. Inventory of forest and rangeland resources, including forest stress. [Atlanta, Georgia, Black Hills, and Manitou, Colorado test sites

    Science.gov (United States)

    Heller, R. C.; Aldrich, R. C.; Weber, F. P.; Driscoll, R. S. (Principal Investigator)

    1974-01-01

    The author has identified the following significant results. Some current beetle-killed ponderosa pine can be detected on S190-B photography imaged over the Bear Lodge mountains in the Black Hills National Forest. Detections were made on SL-3 imagery (September 13, 1973) using a zoom lens microscope to view the photography. At this time correlations have not been made to all of the known infestation spots in the Bear Lodge mountains; rather, known infestations have been located on the SL-3 imagery. It was determined that the beetle-killed trees were current kills by stereo viewing of SL-3 imagery on one side and SL-2 on the other. A successful technique was developed for mapping current beetle-killed pine using MSS imagery from mission 247 flown by the C-130 over the Black Hills test site in September 1973. Color enhancement processing on the NASA/JSC, DAS system using three MSS channels produced an excellent quality detection map for current kill pine. More importantly it provides a way to inventory the dead trees by relating PCM counts to actual numbers of dead trees.

  12. "Iron-Clad" Evidence For Spinning Black Hole

    Science.gov (United States)

    2003-09-01

    Telltale X-rays from iron may reveal if black holes are spinning or not, according to astronomers using NASA's Chandra X-ray Observatory and the European Space Agency's XMM-Newton Observatory. The gas flows and bizarre gravitational effects observed near stellar black holes are similar to those seen around supermassive black holes. Stellar black holes, in effect, are convenient `scale models' of their much larger cousins. Black holes come in at least two different sizes. Stellar black holes are between five and 20 times the mass of the Sun. At the other end of the size scale, supermassive black holes contain millions or billions times the mass of our Sun. The Milky Way contains both a supermassive black hole at its center, as well as a number of stellar black holes sprinkled throughout the Galaxy. At a press conference at the "Four Years of Chandra" symposium in Huntsville, Ala., Jon Miller of the Harvard-Smithsonian Center for Astrophysics in Cambridge, Mass. discussed recent results on the X-ray spectra, or distribution of X-rays with energy, from the iron atoms in gas around three stellar black holes in the Milky Way. "Discovering the high degree of correspondence between stellar and supermassive black holes is a real breakthrough," said Miller. "Because stellar black holes are smaller, everything happens about a million times faster, so they can be used as a test-bed for theories of how spinning black holes affect the space and matter around them." X-rays from a stellar black hole are produced when gas from a nearby companion star is heated to tens of millions of degrees as it swirls toward the black hole. Iron atoms in this gas produce distinctive X-ray signals that can be used to study the orbits of particles around the black hole. For example, the gravity of a black hole can shift the X-rays to lower energies. "The latest work provides the most precise measurements yet of the X-ray spectra for stellar black holes," said Miller. "These data help rule out

  13. A Dancing Black Hole

    Science.gov (United States)

    Shoemaker, Deirdre; Smith, Kenneth; Schnetter, Erik; Fiske, David; Laguna, Pablo; Pullin, Jorge

    2002-04-01

    Recently, stationary black holes have been successfully simulated for up to times of approximately 600-1000M, where M is the mass of the black hole. Considering that the expected burst of gravitational radiation from a binary black hole merger would last approximately 200-500M, black hole codes are approaching the point where simulations of mergers may be feasible. We will present two types of simulations of single black holes obtained with a code based on the Baumgarte-Shapiro-Shibata-Nakamura formulation of the Einstein evolution equations. One type of simulations addresses the stability properties of stationary black hole evolutions. The second type of simulations demonstrates the ability of our code to move a black hole through the computational domain. This is accomplished by shifting the stationary black hole solution to a coordinate system in which the location of the black hole is time dependent.

  14. Math Readiness and Preparation for Competitive College Majors and Careers: The Case of Black Students.

    Science.gov (United States)

    Thomas, Gail E.

    This study examines factors that determine the enrollment of black students in the high school math courses (i.e., advanced algebra, trigonometry, calculus) that are necessary for competitive college and major field access. The data are from a local college survey of juniors and seniors who were enrolled in eight (8) local public and private…

  15. Preparation and characterization of magnetic gene vectors for targeting gene delivery

    Energy Technology Data Exchange (ETDEWEB)

    Zheng, S.W.; Liu, G. [College of Chemistry, Chemical Engineering and Materials Science and Key Laboratory of Organic Synthesis of Jiangsu Province, Soochow University, SIP, Suzhou 215123 (China); Hong, R.Y., E-mail: rhong@suda.edu.cn [College of Chemistry, Chemical Engineering and Materials Science and Key Laboratory of Organic Synthesis of Jiangsu Province, Soochow University, SIP, Suzhou 215123 (China); State Key Laboratory of Multi-phase Complex Systems, Institute of Process Engineering, Chinese Academy of Sciences, Beijing 100080 (China); Li, H.Z. [State Key Laboratory of Multi-phase Complex Systems, Institute of Process Engineering, Chinese Academy of Sciences, Beijing 100080 (China); Li, Y.G., E-mail: ilguoliang@sohu.com [Department of radiology, the First Affiliated Hospital of Soochow University, Suzhou 215007 (China); Wei, D.G., E-mail: dougwei@deas.harvard.edu [Center for Nanoscale Systems, School of Engineering and Applied Science, Harvard University, 11 Oxford Street, Cambridge, MA 02139 (United States)

    2012-10-15

    Highlights: Black-Right-Pointing-Pointer PEI is ideal candidate polymer for the design of gene delivery systems. Black-Right-Pointing-Pointer PEI-CMD-MNPs exhibited a typical superparamagnetic behavior. Black-Right-Pointing-Pointer PEI-CMD-MNPs were well stable over the entire range of pH and NaCl concentration. Black-Right-Pointing-Pointer DNA-PEI-CMD-MNPs transfected cells by a magnet have higher transfection efficiency and gene expression efficiency. - Abstract: The PEI-CMD-MNPs were successfully prepared by the surface modification of magnetic Fe{sub 3}O{sub 4} nanoparticles with carboxymethyl dextran (CMD) and polyethyleneimine (PEI). The PEI-CMD-MNPs polyplexes exhibited a typical superparamagnetic behavior and were well stable over the entire range of pH and NaCl concentration. These PEI-CMD-MNPs were used as magnetic gene vectors for targeting gene delivery. The prepared MNPs at different surface modification stages were characterized using Fourier transform infrared (FT-IR), thermogravimetric analysis (TGA), field emissions canning electron microscopy (FE-SEM), powder X-ray diffraction (XRD) and dynamic laser light scattering (DLS) analysis. The magnetic properties were studied by vibrating sample magnetometer (VSM). To evaluate the performance of the magnetic nanoparticles as gene transfer vector, the PEI-CMD-MNPs were used to delivery green fluorescent protein (GFP) gene into BHK21 cells. The expression of GFP gene was detected by fluorescence microscope. DNA-PEI-CMD-MNPs polyplexes absorbed by the cells were also monitored by Magnetic resonance imaging (MRI). The transfection efficiency and gene expression efficiency of that transfected with a magnet were much higher than that of standard transfection.

  16. SSL/TLS Vulnerability Detection Using Black Box Approach

    Science.gov (United States)

    Gunawan, D.; Sitorus, E. H.; Rahmat, R. F.; Hizriadi, A.

    2018-03-01

    Socket Secure Layer (SSL) and Transport Layer Security (TLS) are cryptographic protocols that provide data encryption to secure the communication over a network. However, in some cases, there are vulnerability found in the implementation of SSL/TLS because of weak cipher key, certificate validation error or session handling error. One of the most vulnerable SSL/TLS bugs is heartbleed. As the security is essential in data communication, this research aims to build a scanner that detect the SSL/TLS vulnerability by using black box approach. This research will focus on heartbleed case. In addition, this research also gathers information about existing SSL in the server. The black box approach is used to test the output of a system without knowing the process inside the system itself. For testing purpose, this research scanned websites and found that some of the websites still have SSL/TLS vulnerability. Thus, the black box approach can be used to detect the vulnerability without considering the source code and the process inside the application.

  17. Investigation of electrokinetic and electrorheological properties of polyindole prepared in the presence of a surfactant

    Energy Technology Data Exchange (ETDEWEB)

    Unal, H. Ibrahim, E-mail: hiunal@gazi.edu.tr [Gazi University, Chemistry Department, Smart Materials Research Lab., Ankara (Turkey); Sahan, Bekir; Erol, Ozlem [Gazi University, Chemistry Department, Smart Materials Research Lab., Ankara (Turkey)

    2012-05-15

    Highlights: Black-Right-Pointing-Pointer Aggregated morphology was determined for PIN, spherical and porous hollows and everniae form morphologies were recorded for SPIN. Black-Right-Pointing-Pointer The PIN/SO and SPIN/SO systems showed almost similar electrokinetic attitudes and a typical shear thinning non-Newtonian viscoelastic behavior, vibration damping capability at elevated frequencies, and enhanced storage moduli with increasing temperature. Black-Right-Pointing-Pointer Non-linear recoverable viscoelastic manner was revealed from the creep-recovery experiments under external electric field. - Abstract: In this study, synthesis of polyindole (PIN) was carried out without and with the presence of a sodium dodecyl sulfate (SDS) surfactant (SPIN), using FeCl{sub 3} as an oxidizing agent. The synthesized materials were subjected to various characterizations techniques namely: particle size, magnetic susceptibility, elemental analysis, density, conductivity, dielectric constant, FTIR, {sup 1}H NMR, TGA, XRD, and SEM. Characterization results revealed the successful preparation of the homopolymers of PIN and SPIN. Zeta ({zeta})-potentials of the samples were measured in aqueous and non-aqueous (silicone oil, SO) media. Electrokinetic properties of PIN and SPIN in aqueous media were determined by {zeta}-potential measurements in the presence of various electrolytes (NaCl, BaCl{sub 2}, AlCl{sub 3}, Na{sub 2}SO{sub 4}) and surfactants (cetyltrimethyl ammonium bromide, SDS, and Triton X-100). Besides, the effect of pH onto {zeta}-potentials of the materials was also examined. The suspensions prepared in SO were subjected to external electric field strength and their electrorheological (ER) properties were investigated. Then the effects of shear rate, frequency, and temperature onto ER activities of the suspensions were examined. Further, creep and creep-recovery tests were applied to the PIN/SO and SPIN/SO suspension systems and reversible non-linear viscoelastic

  18. And still WE rise: Parent-child relationships, resilience, and school readiness in low-income urban Black families.

    Science.gov (United States)

    Anderson, Riana Elyse

    2018-02-01

    The Family Stress Model acknowledges forms of resilience in the face of hardship; however, few studies have emerged on the potentially positive role of familial relationships in the academic, psychological, and prosocial success of impoverished Black children. The current study evaluates how parent-child relationship conflict and financial stress are associated with children's school readiness (i.e., academic, psychosocial, and socioemotional indicators). Latent profile analyses, incorporating financial stress, general stress, and parent-child relationship variables were used to test whether varying family stress profiles differentially predicted children's school readiness in Black families with children entering kindergarten (N = 292). Findings revealed 4 latent classifications with profiles of low, moderate, moderate/high, and high/moderate stress and conflict variables, respectively. Whereas the low-profile was associated with the most desirable school readiness indicators overall, children in the high/moderate-profile were rated as significantly more psychosocially and socioemotionally prepared for school than their moderate/high-profile counterparts. Families with less conflictual parent-child relationships had more optimal school readiness relative to families with higher conflict and less financial strain. The findings of the current study have the potential to contribute to theories of poverty and parent-child relationships, as well as guide therapeutic services focused on family relationships through school- and community-related programs for impoverished urban Black youth and their families. (PsycINFO Database Record (c) 2018 APA, all rights reserved).

  19. Black home, black looks: Identity and socialization in black and interracials families

    Directory of Open Access Journals (Sweden)

    Angela Ernestina Brito

    2013-07-01

    Full Text Available This study aims at aprehending how and in what circumstances families formed by couples of different ethnic-racial origins, being one black and one white, prepare and/or assist their children to face the discrimination the might undergo in consequence of racism againt afro-americans. In oerder to achieve the goal, parents and children of two interracial families were interviewed, in a total of seven interviews. We tried to deepen the knowledge on socilization of mixed offsprings within interracial families, from the statements of the parents and the child. The data obtained and analyzed allow us to conclude that the families use up some strategies to assist hteir children in facing the problem of racism and racial discrimination, even though there are difficulties in elaborating them, and they do not constitute, at least apparently, a priority in children education. However, it was possible to observe that there is a construction of racial belonging, and orientation on possible discriminatory acts kids may undergo. Thus, the orientation is associated to discriminatory experiences lived by the children within the expanded family, at school, on the street, in clubs, being attached to strong affective bonds.

  20. Weak cosmic censorship, dyonic Kerr–Newman black holes and Dirac fields

    International Nuclear Information System (INIS)

    Tóth, Gábor Zsolt

    2016-01-01

    It was investigated recently, with the aim of testing the weak cosmic censorship conjecture, whether an extremal Kerr black hole can be converted into a naked singularity by interaction with a massless classical Dirac test field, and it was found that this is possible. We generalize this result to electrically and magnetically charged rotating extremal black holes (i.e. extremal dyonic Kerr–Newman black holes) and massive Dirac test fields, allowing magnetically or electrically uncharged or nonrotating black holes and the massless Dirac field as special cases. We show that the possibility of the conversion is a direct consequence of the fact that the Einstein–Hilbert energy-momentum tensor of the classical Dirac field does not satisfy the null energy condition, and is therefore not in contradiction with the weak cosmic censorship conjecture. We give a derivation of the absence of superradiance of the Dirac field without making use of the complete separability of the Dirac equation in the dyonic Kerr–Newman background, and we determine the range of superradiant frequencies of the scalar field. The range of frequencies of the Dirac field that can be used to convert a black hole into a naked singularity partially coincides with the superradiant range of the scalar field. We apply horizon-penetrating coordinates, as our arguments involve calculating quantities at the event horizon. We describe the separation of variables for the Dirac equation in these coordinates, although we mostly avoid using it. (paper)

  1. Electromagnetic perturbations of black holes in general relativity coupled to nonlinear electrodynamics

    Science.gov (United States)

    Toshmatov, Bobir; Stuchlík, Zdeněk; Schee, Jan; Ahmedov, Bobomurat

    2018-04-01

    The electromagnetic (EM) perturbations of the black hole solutions in general relativity coupled to nonlinear electrodynamics (NED) are studied for both electrically and magnetically charged black holes, assuming that the EM perturbations do not alter the spacetime geometry. It is shown that the effective potentials of the electrically and magnetically charged black holes related to test perturbative NED EM fields are related to the effective metric governing the photon motion, contrary to the effective potential of the linear electrodynamic (Maxwell) field that is related to the spacetime metric. Consequently, corresponding quasinormal (QN) frequencies differ as well. As a special case, we study new family of the NED black hole solutions which tend in the weak field limit to the Maxwell field, giving the Reissner-Nordström (RN) black hole solution. We compare the NED Maxwellian black hole QN spectra with the RN black hole QN spectra.

  2. Can superconducting cosmic strings piercing seed black holes generate supermassive black holes in the early universe?

    Energy Technology Data Exchange (ETDEWEB)

    Lake, Matthew J. [The Institute for Fundamental Study, ' ' The Tah Poe Academia Institute' ' , Naresuan University, Phitsanulok (Thailand); Thailand Center of Excellence in Physics, Ministry of Education, Bangkok (Thailand); Harko, Tiberiu [Department of Physics, Babes-Bolyai University, Cluj-Napoca (Romania); Department of Mathematics, University College London (United Kingdom)

    2017-10-15

    The discovery of a large number of supermassive black holes (SMBH) at redshifts z > 6, when the Universe was only 900 million years old, raises the question of how such massive compact objects could form in a cosmologically short time interval. Each of the standard scenarios proposed, involving rapid accretion of seed black holes or black hole mergers, faces severe theoretical difficulties in explaining the short-time formation of supermassive objects. In this work we propose an alternative scenario for the formation of SMBH in the early Universe, in which energy transfer from superconducting cosmic strings piercing small seed black holes is the main physical process leading to rapid mass increase. As a toy model, the accretion rate of a seed black hole pierced by two antipodal strings carrying constant current is considered. Using an effective action approach, which phenomenologically incorporates a large class of superconducting string models, we estimate the minimum current required to form SMBH with masses of order M = 2 x 10{sup 9} M {sub CircleDot} by z = 7.085. This corresponds to the mass of the central black hole powering the quasar ULAS J112001.48+064124.3 and is taken as a test case scenario for early-epoch SMBH formation. For GUT scale strings, the required fractional increase in the string energy density, due to the presence of the current, is of order 10{sup -7}, so that their existence remains consistent with current observational bounds on the string tension. In addition, we consider an ''exotic'' scenario, in which an SMBH is generated when a small seed black hole is pierced by a higher-dimensional F-string, predicted by string theory. We find that both topological defect strings and fundamental strings are able to carry currents large enough to generate early-epoch SMBH via our proposed mechanism. (copyright 2017 WILEY-VCH Verlag GmbH and Co. KGaA, Weinheim)

  3. Biological control of banana black Sigatoka disease with Trichoderma

    Directory of Open Access Journals (Sweden)

    Poholl Adan Sagratzki Cavero

    2015-06-01

    Full Text Available Black Sigatoka disease caused by Mycosphaerella fijiensis is the most severe banana disease worldwide. The pathogen is in an invasive phase in Brazil and is already present in most States of the country. The potential of 29 isolates of Trichoderma spp. was studied for the control of black Sigatoka disease under field conditions. Four isolates were able to significantly reduce disease severity and were further tested in a second field experiment. Isolate 2.047 showed the best results in both field experiments and was selected for fungicide sensitivity tests and mass production. This isolate was identified as Trichoderma atroviride by sequencing fragments of the ITS region of the rDNA and tef-1α of the RNA polymerase. Trichoderma atroviride was as effective as the fungicide Azoxystrobin, which is recommended for controlling black Sigatoka. This biocontrol agent has potential to control the disease and may be scaled-up for field applications on rice-based solid fermentation

  4. Stationary black holes with stringy hair

    Science.gov (United States)

    Boos, Jens; Frolov, Valeri P.

    2018-01-01

    We discuss properties of black holes which are pierced by special configurations of cosmic strings. For static black holes, we consider radial strings in the limit when the number of strings grows to infinity while the tension of each single string tends to zero. In a properly taken limit, the stress-energy tensor of the string distribution is finite. We call such matter stringy matter. We present a solution of the Einstein equations for an electrically charged static black hole with the stringy matter, with and without a cosmological constant. This solution is a warped product of two metrics. One of them is a deformed 2-sphere, whose Gaussian curvature is determined by the energy density of the stringy matter. We discuss the embedding of a corresponding distorted sphere into a three-dimensional Euclidean space and formulate consistency conditions. We also found a relation between the square of the Weyl tensor invariant of the four-dimensional spacetime of the stringy black holes and the energy density of the stringy matter. In the second part of the paper, we discuss test stationary strings in the Kerr geometry and in its Kerr-NUT-(anti-)de Sitter generalizations. Explicit solutions for strings that are regular at the event horizon are obtained. Using these solutions, the stress-energy tensor of the stringy matter in these geometries is calculated. Extraction of the angular momentum from rotating black holes by such strings is also discussed.

  5. A topological extension of GR: Black holes induce dark energy

    International Nuclear Information System (INIS)

    Spaans, M

    2013-01-01

    A topological extension of general relativity is presented. The superposition principle of quantum mechanics, as formulated by the Feynman path integral, is taken as a starting point. It is argued that the trajectories that enter this path integral are distinct and thus that space-time topology is multiply connected. Specifically, space-time at the Planck scale consists of a lattice of three-tori that facilitates many distinct paths for particles to travel along. To add gravity, mini black holes are attached to this lattice. These mini black holes represent Wheeler's quantum foam and result from the fact that GR is not conformally invariant. The number of such mini black holes in any time-slice through four-space is found to be equal to the number of macroscopic (so long-lived) black holes in the entire universe. This connection, by which macroscopic black holes induce mini black holes, is a topological expression of Mach's principle. The proposed topological extension of GR can be tested because, if correct, the dark energy density of the universe should be proportional the total number of macroscopic black holes in the universe at any time. This prediction, although strange, agrees with current astrophysical observations.

  6. Sizes of Black Holes Throughout the Universe

    Science.gov (United States)

    Kohler, Susanna

    2018-05-01

    higher-mass black holes.A team of scientists led by Pierre Christian, an Einstein Fellow at Harvard University, has now looked into characterizing this shift. In particular, Christian and collaborators explore how black-hole mergers in the centers of dense star clustersultimately shape the black-hole mass function of the universe.Black Holes TodayChristian and collaborators use analytical models of coagulation mergers of particles to form larger particles to estimate the impact of mergers in star clusters on resulting black-hole sizes. They find that, over an evolution of 10 billion years, mergers can appreciably fill in the upper mass gap of the black-hole IMF.An example of the black-hole mass function that can result from evolving the initial mass function complete with gaps over time. Two breaks appear as a result of the initial gaps: one at 10 (LB) and one at 60 solar masses (UB). [Christian et al. 2018]The lower mass gap, on the other hand, leaves observable signatures in the final black-hole mass function: a break at 10 solar masses (since black holes below this mass cant be created by mergers) and one at 60 solar masses (caused by the interaction of the upper and lower gaps). As we build up black-hole statistics in the future (thanks, gravitational-wave detectors!), searching for these breaks will help us to test our models.Lastly, the authors find that their models can only be consistent with observations if ejection is efficient black holes must be regularly ousted from star clusters through interactions with other bodies or as a result of kicks when they merge. This idea is consistent with many recent studies supporting a large population of free-floating stellar-mass black holes.CitationPierre Christian et al 2018 ApJL 858 L8. doi:10.3847/2041-8213/aabf88

  7. 77 FR 18997 - Rim Lakes Forest Restoration Project; Apache-Sitgreavese National Forest, Black Mesa Ranger...

    Science.gov (United States)

    2012-03-29

    ... DEPARTMENT OF AGRICULTURE Forest Service Rim Lakes Forest Restoration Project; Apache-Sitgreavese National Forest, Black Mesa Ranger District, Coconino County, AZ AGENCY: Forest Service, USDA. ACTION: Notice of intent to prepare an environmental impact statement. SUMMARY: The U.S. Forest Service (FS) will...

  8. Electrical conductivity of compacts of graphene, multi-wall carbon nanotubes, carbon black, and graphite powder

    NARCIS (Netherlands)

    Marinho, B.; Gomes Ghislandi, M.; Tkalya, E.; Koning, C.E.; With, de G.

    2012-01-01

    The electrical conductivity of different carbon materials (multi-walled carbon nanotubes, graphene, carbon black and graphite), widely used as fillers in polymeric matrices, was studied using compacts produced by a paper preparation process and by powder compression. Powder pressing assays show that

  9. Bulk emission by higher-dimensional black holes: almost perfect blackbody radiation

    International Nuclear Information System (INIS)

    Hod, Shahar

    2011-01-01

    We study the Hawking radiation emitted into the bulk by (D + 1)-dimensional Schwarzschild black holes. It is well known that the black-hole spectrum departs from exact blackbody form due to the frequency dependence of the 'greybody' factors. For intermediate values of D (3 ≤ D ∼ > 1, the typical wavelengths in the black-hole spectrum are much shorter than the size of the black hole. In this regime, the greybody factors are well described by the geometric-optics approximation according to which they are almost frequency independent. Following this observation, we argue that for higher-dimensional black holes with D >> 1, the total power emitted into the bulk should be well approximated by the analytical formula for perfect blackbody radiation. We test the validity of this analytical prediction with numerical computations.

  10. Preparation of supported electrocatalyst comprising multiwalled carbon nanotubes

    Science.gov (United States)

    Wu, Gang; Zelenay, Piotr

    2013-08-27

    A process for preparing a durable non-precious metal oxygen reduction electrocatalyst involves heat treatment of a ball-milled mixture of polyaniline and multiwalled carbon nanotubes in the presence of a Fe species. The catalyst is more durable than catalysts that use carbon black supports. Performance degradation was minimal or absent after 500 hours of operation at constant cell voltage of 0.40 V.

  11. Fragrance patch tests prepared in advance may give false-negative reactions.

    Science.gov (United States)

    Mowitz, Martin; Svedman, Cecilia; Zimerson, Erik; Bruze, Magnus

    2014-11-01

    Several of the ingredients in fragrance mix I (FM I) have been shown to evaporate from petrolatum preparations applied in test chambers to an extent that can be suspected to affect the patch test result. To compare the reactivity towards FM I and fragrance mix II (FM II) when they are applied in test chambers in advance and immediately prior to the patch test occasion. Seven hundred and ninety-five consecutive patients were simultaneously patch tested with duplicate samples of FM I and FM II. One sample was applied in the test chamber 6 days in advance (6D sample), and the other sample was applied immediately before the patients were patch tested (fresh sample). Twenty-two (2.8%) patients reacted exclusively to the fresh sample of FM I, 6 (0.7%) reacted exclusively to the 6D sample, and 22 (2.8%) reacted to both samples. The corresponding numbers for FM II were 9 (1.1%) for the fresh sample, 6 (0.7%) for the 6D sample and 12 (1.5%) for both samples. There was a statistically significant difference between the numbers of patients reacting to the fresh and 6D samples of FM I. No corresponding difference was observed for FM II. This can probably be explained by differences in volatilities between the ingredients of FM I and FM II. © 2014 John Wiley & Sons A/S. Published by John Wiley & Sons Ltd.

  12. Astrophysical black holes

    CERN Document Server

    Gorini, Vittorio; Moschella, Ugo; Treves, Aldo; Colpi, Monica

    2016-01-01

    Based on graduate school lectures in contemporary relativity and gravitational physics, this book gives a complete and unified picture of the present status of theoretical and observational properties of astrophysical black holes. The chapters are written by internationally recognized specialists. They cover general theoretical aspects of black hole astrophysics, the theory of accretion and ejection of gas and jets, stellar-sized black holes observed in the Milky Way, the formation and evolution of supermassive black holes in galactic centers and quasars as well as their influence on the dynamics in galactic nuclei. The final chapter addresses analytical relativity of black holes supporting theoretical understanding of the coalescence of black holes as well as being of great relevance in identifying gravitational wave signals. With its introductory chapters the book is aimed at advanced graduate and post-graduate students, but it will also be useful for specialists.

  13. Extruded black gram flour: Partial substitute for improving quality characteristics of Indian traditional snack

    Directory of Open Access Journals (Sweden)

    Laxmi Ananthanarayan

    2018-03-01

    Full Text Available Background: During extrusion of black gram flour, formation of amylose-lipid complexes lowers down the gelatinization enthalpy of extrudates, and the partially gelatinized black gram starch leads to lowering down the water-holding capacity and alters functional properties resulting in changing quality attributes of the end product on frying/microwaving/roasting. Methods: Attempts have been made to improve the quality of an Indian traditional snack (e.g., papad by incorporating extruded black gram flour as partial substitute for raw (unextruded black gram flour. In present work, overall quality improvement was achieved by analyzing prefrying and postfrying characteristics (diameter, moisture content, expansion ratio, oil uptake, texture, and color of papad and physical properties (color and viscosity of fried oil. Results: Four different papad samples were prepared (control papads without addition of papadkhar, papads with use of 3% papadkhar, papads with incorporation of extruded black gram flour at 25% concentration, papads with incorporation of extruded black gram flour at 50% concentration along with 1% papadkhar and analyzed along standard market sample. Incorporation of extruded black gram flour in papad resulted in greater expansion with less oil uptake in fried papad. Further addition of extruded black gram flour permitted the use of lower concentration of papadkhar. After frying, the quality of oil was characterized after numerous frying cycles. Conclusion: Oil used for frying of papads containing highest concentration of papadkhar was effective only up to two frying cycles, after which color and viscosity increased significantly, adversely affecting the quality of fried oil. Keywords: Black gram flour, Extrusion, Prefrying and postfrying characteristics of papad, Quality of fried oil

  14. The rising star of 2D black phosphorus beyond graphene: synthesis, properties and electronic applications

    Science.gov (United States)

    Chen, Pengfei; Li, Neng; Chen, Xingzhu; Ong, Wee-Jun; Zhao, Xiujian

    2018-01-01

    Black phosphorus, which is a relatively rare allotrope of phosphorus, was first discovered by Bridgman in 1914. Since the advent of two-dimensional (2D) black phosphorus (which is known as phosphorene due to its resembling graphene sheets) in early 2014, research interest in the arena of black phosphorus was reignited in the scientific and technological communities. Henceforth, a myriad of research studies on this new member of the 2D world have been extensively emerged. Fascinatingly, 2D black phosphorus exhibits a distinctive wrinkled structure with the high hole mobility up to 1000 cm2 V-1 s-1, excellent mechanical properties, tunable band structures, anisotropic thermal, electrical and optical properties, thus leading to its marvelous prospects in device applications. This review firstly introduces the state-of-the-art development, structural properties and preparation routes of black phosphorus. In particular, anisotropy involved in mechanical properties, thermal conductivity, carrier transport as well as optical properties is comprehensively discussed. Apart from discussing the recent progress in black phosphorus which is applied to devices (i.e. field effect transistors and optoelectronic), the review also highlights the bottlenecks encountered by the society and finally casts an invigorating perspective and insightful outlook on the future direction of the next-generation 2D black phosphorus by harnessing its remarkable characteristics for energy production.

  15. Lumpy AdS5× S5 black holes and black belts

    International Nuclear Information System (INIS)

    Dias, Óscar J.C.; Santos, Jorge E.; Way, Benson

    2015-01-01

    Sufficiently small Schwarzschild black holes in global AdS 5 ×S 5 are Gregory-Laflamme unstable. We construct new families of black hole solutions that bifurcate from the onset of this instability and break the full SO(6) symmetry group of the S 5 down to SO(5). These new “lumpy" solutions are labelled by the harmonics ℓ. We find evidence that the ℓ=1 branch never dominates the microcanonical/canonical ensembles and connects through a topology-changing merger to a localised black hole solution with S 8 topology. We argue that these S 8 black holes should become the dominant phase in the microcanonical ensemble for small enough energies, and that the transition to Schwarzschild black holes is first order. Furthermore, we find two branches of solutions with ℓ=2. We expect one of these branches to connect to a solution containing two localised black holes, while the other branch connects to a black hole solution with horizon topology S 4 ×S 4 which we call a “black belt”.

  16. Black holes in binary stars

    NARCIS (Netherlands)

    Wijers, R.A.M.J.

    1996-01-01

    Introduction Distinguishing neutron stars and black holes Optical companions and dynamical masses X-ray signatures of the nature of a compact object Structure and evolution of black-hole binaries High-mass black-hole binaries Low-mass black-hole binaries Low-mass black holes Formation of black holes

  17. Copper, zinc, molybdenum and uranium distribution in bottom sediments of the Black Sea

    International Nuclear Information System (INIS)

    Zhorov, V.A.; Sovga, E.E.; Solov'eva, L.B.; Oguslavskij, P.G.; Babinets, A.E.; AN Ukrainskoj SSR, Kiev. Inst. Geologicheskikh Nauk)

    1983-01-01

    The results of investigations of bottom sediments of the Black Sea by four expeditions aboard scientific ships ''Academician Vernadsky'', ''Michael Lomonosov'', ''Academician Vavilov'' in 1972-1978, are presented. 70 columns of bottom sediments are studied, about 200 samples are analyzed for Cu, Zn, Mo and U using chemical methods with photometric ending. Charts of Cu, Zn, Mo and U distribution in modern, ancient Black Sea and neoeuxenic sediments of the basin are prepared. Preferable uranium concentration in modern sediments, copper and molybdenum - in sapropelic muds of ancient Black Sea sediments and zinc - in neoeuxenic layers, is shown. Uranium geochemical behaviour is determined by physico-chemical regime of the basin, the presence of restoring situation which promotes the formation of uranium sorption-active forms in the upper layer of modern sediments. Neither sapropelite (organic matter), nor the peculiarities of lithological composition of sediments affect uranium behaviour

  18. Black Interpretation, Black American Literature, and Grey Audiences.

    Science.gov (United States)

    Washington, Earl M.

    1981-01-01

    Defines and illustrates language techniques used by Black authors writing to and for Blacks in the 1960s and 1970s. Suggests how language and theme barriers of such literature might be overcome in a contemporary integrated oral interpretation classroom. (PD)

  19. #BlackBabiesMatter: Analyzing Black Religious Media in Conservative and Progressive Evangelical Communities

    Directory of Open Access Journals (Sweden)

    Monique Moultrie

    2017-11-01

    Full Text Available This article explores how conservative and progressive black Protestants interrogate the theological theme of the sacrality of black life through digital media. The innovations of religious media in black evangelical communities remain an understudied phenomenon in African American religion, making this an apt arena for further discovery. This current intervention into the study of African American Religion examines digital activism through examples of religious media produced by blacks for black audiences. This article begins its interrogation of the sacrality of black life by juxtaposing those who contend that Black Babies Matter as pro-birth-oriented, religiously motivated activists with those religious opponents asserting Black Lives Matter who present an intersectional pro-life approach. The comparison of views relies on womanist cultural analysis as its main methodology to analyze and interpret digital media and explore its ramifications for African American Religion.

  20. Radical-scavenging-linked antioxidant activities of extracts from black chokeberry and blueberry cultivated in Korea.

    Science.gov (United States)

    Hwang, Seok Joon; Yoon, Won Byong; Lee, Ok-Hwan; Cha, Seung Ju; Kim, Jong Dai

    2014-03-01

    The objective of this study was to investigate the radical-scavenging-linked antioxidant properties of the extracts from black chokeberry and blueberry cultivated in Korea. The 70% ethanol extracts were prepared from black chokeberry and blueberry, and evaluated for total phenolic content, total flavonoid content, total proanthocyanidin content, and antioxidative activities, using various in vitro assays, such as DPPH(2,2-diphenyl-1-picrylhydrazyl), ABTS(2,2-azino-bis-(3-ethylenebenzothiozoline-6-sulphonic acid)) radical-scavenging activity, FRAP(ferric-reducing antioxidant power) and reducing power. The major phenolic compounds, including cyanidin-3-galactoside, cyanidin-3-arabinoside, neochlorogenic acid, procyanidin B1, were analysed by HPLC with a photodiode array detector. Results showed that total phenol, flavonoid and proanthocyanidin contents of black chokeberry extract were higher than those of blueberry extract. In addition, black chokeberry extract exhibited higher free radical-scavenging activity and reducing power than did blueberry extract. Cyanidin-3-galactoside was identified as a major phenolic compound, with considerable content in black chokeberry, that correlated with its higher antioxidant and radical-scavenging effects. These results suggest that black chokeberry extracts could be considered as a good source of natural antioxidants and functional food ingredients. Copyright © 2013 Elsevier Ltd. All rights reserved.

  1. Black holes. Chapter 6

    International Nuclear Information System (INIS)

    Penrose, R.

    1980-01-01

    Conditions for the formation of a black hole are considered, and the properties of black holes. The possibility of Cygnus X-1 as a black hole is discussed. Einstein's theory of general relativity in relation to the formation of black holes is discussed. (U.K.)

  2. [Phosphorus transfer between mixed poplar and black locust seedlings].

    Science.gov (United States)

    He, Wei; Jia, Liming; Hao, Baogang; Wen, Xuejun; Zhai, Mingpu

    2003-04-01

    In this paper, the 32P radio-tracer technique was applied to study the ways of phosphorus transfer between poplar (Populus euramericana cv. 'I-214') and black locust (Robinia pseudoacacia). A five compartment root box (18 cm x 18 cm x 26 cm) was used for testing the existence of the hyphal links between the roots of two tree species when inoculated with vesicular-arbuscular (VA) mycorrhizal fungus (Glomus mosseae). Populus I-214 (donor) and Robinia pseudoacacia (receiver) were grown in two terminal compartments, separated by a 2 cm root-free soil layer. The root compartments were lined with bags of nylon mesh (38 microns) that allowed the passage of hyphae but not roots. The top soil of a mixed stand of poplar and black locust, autoclaved at 121 degrees C for one hour, was used for growing seedlings for testing. In 5 compartment root box, mycorrhizal root colonization of poplar was 34%, in which VA mycorrhizal fungus was inoculated, whereas 26% mycorrhizal root colonization was observed in black locust, the other terminal compartment, 20 weeks after planting. No root colonization was observed in non-inoculated plant pairs. This indicated that the mycorrhizal root colonization of black locust was caused by hyphal spreading from the poplar. Test of tracer isotope of 32P showed that the radioactivity of the treatment significantly higher than that of the control (P mycorrhizal fungus was inoculated in poplar root. Furthermore, mycorrhizal interconnections between the roots of poplar and black locust seedlings was observed in situ by binocular in root box. All these experiments showed that the hyphal links was formed between the roots of two species of trees inoculated by VA mycorrhizal fungus. Four treatments were designed according to if there were two nets (mesh 38 microns), 2 cm apart, between the poplar and black locust, and if the soil in root box was pasteurized. Most significant differences of radioactivity among four treatments appeared 44 days after feeding

  3. Black ringoids: spinning balanced black objects in d≥5 dimensions — the codimension-two case

    International Nuclear Information System (INIS)

    Kleihaus, Burkhard; Kunz, Jutta; Radu, Eugen

    2015-01-01

    We propose a general framework for the study of asymptotically flat black objects with k+1 equal magnitude angular momenta in d≥5 spacetime dimensions (with 0≤k≤[((d−5)/2)]). In this approach, the dependence on all angular coordinates but one is factorized, which leads to a codimension-two problem. This framework can describe black holes with spherical horizon topology, the simplest solutions corresponding to a class of Myers-Perry black holes. A different set of solutions describes balanced black objects with S"n"+"1×S"2"k"+"1 horizon topology. The simplest members of this family are the black rings (k=0). The solutions with k>0 are dubbed black ringoids. Based on the nonperturbative numerical results found for several values of (n,k), we propose a general picture for the properties and the phase diagram of these solutions and the associated black holes with spherical horizon topology: n=1 black ringoids repeat the k=0 pattern of black rings and Myers-Perry black holes in 5 dimensions, whereas n>1 black ringoids follow the pattern of higher dimensional black rings associated with ‘pinched’ black holes and Myers-Perry black holes.

  4. Black theology in South Africa – A theology of human dignity and black identity

    Directory of Open Access Journals (Sweden)

    Timothy van Aarde

    2016-08-01

    Full Text Available Black theology in South Africa is still relevant 20 years after the apartheid regime ended. It is a theology that gave to Black South Africans human dignity and a black identity. Black theology in South Africa confronted the imbalances of power and abusive power structures through an affirmation of human dignity and the uniqueness of the identity of black people. The biblical narrative of the Exodus is a definitive narrative in American black theology and liberation theology in overcoming oppression understood as political victimisation. Black theology in South Africa is not primarily about power and economics but also about the rediscovery of human dignity and black identity and to a lesser extent about victimisation. A third generation of black theology in South Africa will gain impetus through a rediscovery of human dignity and identity as its core values instead of a Black American liberation theology of victimisation or a Marxist liberation theology of the eradication of all power or economic imbalances.

  5. Black molecular adsorber coatings for spaceflight applications

    Science.gov (United States)

    Abraham, Nithin S.; Hasegawa, Mark M.; Straka, Sharon A.

    2014-09-01

    The molecular adsorber coating is a new technology that was developed to mitigate the risk of on-orbit molecular contamination on spaceflight missions. The application of this coating would be ideal near highly sensitive, interior surfaces and instruments that are negatively impacted by outgassed molecules from materials, such as plastics, adhesives, lubricants, epoxies, and other similar compounds. This current, sprayable paint technology is comprised of inorganic white materials made from highly porous zeolite. In addition to good adhesion performance, thermal stability, and adsorptive capability, the molecular adsorber coating offers favorable thermal control characteristics. However, low reflectivity properties, which are typically offered by black thermal control coatings, are desired for some spaceflight applications. For example, black coatings are used on interior surfaces, in particular, on instrument baffles for optical stray light control. Similarly, they are also used within light paths between optical systems, such as telescopes, to absorb light. Recent efforts have been made to transform the white molecular adsorber coating into a black coating with similar adsorptive properties. This result is achieved by optimizing the current formulation with black pigments, while still maintaining its adsorption capability for outgassing control. Different binder to pigment ratios, coating thicknesses, and spray application techniques were explored to develop a black version of the molecular adsorber coating. During the development process, coating performance and adsorption characteristics were studied. The preliminary work performed on black molecular adsorber coatings thus far is very promising. Continued development and testing is necessary for its use on future contamination sensitive spaceflight missions.

  6. Thermodynamics and luminosities of rainbow black holes

    Energy Technology Data Exchange (ETDEWEB)

    Mu, Benrong [Physics Teaching and Research section, College of Medical Technology, Chengdu University of Traditional Chinese Medicine, No. 1166 Liutai Avenue, Chengdu (China); Wang, Peng; Yang, Haitang, E-mail: mubenrong@uestc.edu.cn, E-mail: pengw@scu.edu.cn, E-mail: hyanga@scu.edu.cn [Center for Theoretical Physics, College of Physical Science and Technology, Sichuan University, No. 24 South Section 1 Yihuan Road, Chengdu (China)

    2015-11-01

    Doubly special relativity (DSR) is an effective model for encoding quantum gravity in flat spacetime. As result of the nonlinearity of the Lorentz transformation, the energy-momentum dispersion relation is modified. One simple way to import DSR to curved spacetime is ''Gravity's rainbow'', where the spacetime background felt by a test particle would depend on its energy. Focusing on the ''Amelino-Camelia dispersion relation'' which is E{sup 2} = m{sup 2}+p{sup 2}[1−η(E/m{sub p}){sup n}] with n > 0, we investigate the thermodynamical properties of a Schwarzschild black hole and a static uncharged black string for all possible values of η and n in the framework of rainbow gravity. It shows that there are non-vanishing minimum masses for these two black holes in the cases with η < 0 and n ≥ 2. Considering effects of rainbow gravity on both the Hawking temperature and radius of the event horizon, we use the geometric optics approximation to compute luminosities of a 2D black hole, a Schwarzschild one and a static uncharged black string. It is found that the luminosities can be significantly suppressed or boosted depending on the values of η and n.

  7. Computer Forensic Function Testing: Media Preparation, Write Protection And Verification

    Directory of Open Access Journals (Sweden)

    Yinghua (David Guo

    2010-06-01

    Full Text Available Normal 0 false false false EN-US JA AR-SA The growth in the computer forensic field has created a demand for new software (or increased functionality to existing software and a means to verify that this software is truly forensic i.e. capable of meeting the requirements of the trier of fact. In this work, we review our previous work---a function oriented testing framework for validation and verification of computer forensic tools. This framework consists of three parts: function mapping, requirements specification and reference set development. Through function mapping, we give a scientific and systemical description of the fundamentals of computer forensic discipline, i.e. what functions are needed in the computer forensic investigation process. We focus this paper on the functions of media preparation, write protection and verification. Specifically, we complete the function mapping of these functions and specify their requirements. Based on this work, future work can be conducted to develop corresponding reference sets to test any tools that possess these functions.

  8. Black hole and cosmos with multiple horizons and multiple singularities in vector-tensor theories

    Science.gov (United States)

    Gao, Changjun; Lu, Youjun; Yu, Shuang; Shen, You-Gen

    2018-05-01

    A stationary and spherically symmetric black hole (e.g., Reissner-Nordström black hole or Kerr-Newman black hole) has, at most, one singularity and two horizons. One horizon is the outer event horizon and the other is the inner Cauchy horizon. Can we construct static and spherically symmetric black hole solutions with N horizons and M singularities? The de Sitter cosmos has only one apparent horizon. Can we construct cosmos solutions with N horizons? In this article, we present the static and spherically symmetric black hole and cosmos solutions with N horizons and M singularities in the vector-tensor theories. Following these motivations, we also construct the black hole solutions with a firewall. The deviation of these black hole solutions from the usual ones can be potentially tested by future measurements of gravitational waves or the black hole continuum spectrum.

  9. Probing loop quantum gravity with evaporating black holes.

    Science.gov (United States)

    Barrau, A; Cailleteau, T; Cao, X; Diaz-Polo, J; Grain, J

    2011-12-16

    This Letter aims at showing that the observation of evaporating black holes should allow the usual Hawking behavior to be distinguished from loop quantum gravity (LQG) expectations. We present a full Monte Carlo simulation of the evaporation in LQG and statistical tests that discriminate between competing models. We conclude that contrarily to what was commonly thought, the discreteness of the area in LQG leads to characteristic features that qualify evaporating black holes as objects that could reveal quantum gravity footprints. © 2011 American Physical Society

  10. Black hole hair removal

    International Nuclear Information System (INIS)

    Banerjee, Nabamita; Mandal, Ipsita; Sen, Ashoke

    2009-01-01

    Macroscopic entropy of an extremal black hole is expected to be determined completely by its near horizon geometry. Thus two black holes with identical near horizon geometries should have identical macroscopic entropy, and the expected equality between macroscopic and microscopic entropies will then imply that they have identical degeneracies of microstates. An apparent counterexample is provided by the 4D-5D lift relating BMPV black hole to a four dimensional black hole. The two black holes have identical near horizon geometries but different microscopic spectrum. We suggest that this discrepancy can be accounted for by black hole hair - degrees of freedom living outside the horizon and contributing to the degeneracies. We identify these degrees of freedom for both the four and the five dimensional black holes and show that after their contributions are removed from the microscopic degeneracies of the respective systems, the result for the four and five dimensional black holes match exactly.

  11. Aqueous and hydroalcoholic extracts of Black Maca (Lepidium meyenii) improve scopolamine-induced memory impairment in mice.

    Science.gov (United States)

    Rubio, Julio; Dang, Haixia; Gong, Mengjuan; Liu, Xinmin; Chen, Shi-Lin; Gonzales, Gustavo F

    2007-10-01

    Lepidium meyenii Walp. (Brassicaceae), known as Maca, is a Peruvian hypocotyl growing exclusively between 4,000 and 4,500 m altitude in the central Peruvian Andes, particularly in Junin plateau. Previously, Black variety of Maca showed to be more beneficial than other varieties of Maca on learning and memory in ovariectomized mice on the water finding test. The present study aimed to test two different doses of aqueous (0.50 and 2.00 g/kg) and hydroalcoholic (0.25 and 1.00 g/kg) extracts of Black Maca administered for 35 days on memory impairment induced by scopolamine (1mg/kg body weight i.p.) in male mice. Memory and learning were evaluated using the water Morris maze and the step-down avoidance test. Brain acetylcholinesterase (AChE) and monoamine oxidase (MAO) activities in brain were also determined. Both extracts of Black Maca significantly ameliorated the scopolamine-induced memory impairment as measured in both the water Morris maze and the step-down avoidance tests. Black Maca extracts inhibited AChE activity, whereas MAO activity was not affected. These results indicate that Black Maca improves scopolamine-induced memory deficits.

  12. A Community Network of 100 Black Carbon Sensors

    Science.gov (United States)

    Preble, C.; Kirchstetter, T.; Caubel, J.; Cados, T.; Keeling, C.; Chang, S.

    2017-12-01

    We developed a low-cost black carbon sensor, field tested its performance, and then built and deployed a network of 100 sensors in West Oakland, California. We operated the network for 100 days beginning mid-May 2017 to measure spatially resolved black carbon concentrations throughout the community. West Oakland is a San Francisco Bay Area mixed residential and industrial community that is adjacent to regional port and rail yard facilities and surrounded by major freeways. As such, the community is affected by diesel particulate matter emissions from heavy-duty diesel trucks, locomotives, and ships associated with freight movement. In partnership with Environmental Defense Fund, the Bay Area Air Quality Management District, and the West Oakland Environmental Indicators Project, we deployed the black carbon monitoring network outside of residences and business, along truck routes and arterial streets, and at upwind locations. The sensor employs the filter-based light transmission method to measure black carbon and has good precision and correspondence with current commercial black carbon instruments. Throughout the 100-day period, each of the 100 sensors transmitted data via a cellular network. A MySQL database was built to receive and manage the data in real-time. The database included diagnostic features to monitor each sensor's operational status and facilitate the maintenance of the network. Spatial and temporal patterns in black carbon concentrations will be presented, including patterns around industrial facilities, freeways, and truck routes, as well as the relationship between neighborhood concentrations and the BAAQMD's monitoring site. Lessons learned during this first of its kind black carbon monitoring network will also be shared.

  13. Recurrence network measures for hypothesis testing using surrogate data: Application to black hole light curves

    Science.gov (United States)

    Jacob, Rinku; Harikrishnan, K. P.; Misra, R.; Ambika, G.

    2018-01-01

    Recurrence networks and the associated statistical measures have become important tools in the analysis of time series data. In this work, we test how effective the recurrence network measures are in analyzing real world data involving two main types of noise, white noise and colored noise. We use two prominent network measures as discriminating statistic for hypothesis testing using surrogate data for a specific null hypothesis that the data is derived from a linear stochastic process. We show that the characteristic path length is especially efficient as a discriminating measure with the conclusions reasonably accurate even with limited number of data points in the time series. We also highlight an additional advantage of the network approach in identifying the dimensionality of the system underlying the time series through a convergence measure derived from the probability distribution of the local clustering coefficients. As examples of real world data, we use the light curves from a prominent black hole system and show that a combined analysis using three primary network measures can provide vital information regarding the nature of temporal variability of light curves from different spectroscopic classes.

  14. Managing the Testing Process Practical Tools and Techniques for Managing Hardware and Software Testing

    CERN Document Server

    Black, Rex

    2011-01-01

    New edition of one of the most influential books on managing software and hardware testing In this new edition of his top-selling book, Rex Black walks you through the steps necessary to manage rigorous testing programs of hardware and software. The preeminent expert in his field, Mr. Black draws upon years of experience as president of both the International and American Software Testing Qualifications boards to offer this extensive resource of all the standards, methods, and tools you'll need. The book covers core testing concepts and thoroughly examines the best test management practices

  15. REFRACTORY FOR BLACK LIQUOR GASIFIERS

    Energy Technology Data Exchange (ETDEWEB)

    William L. Headrick Jr; Musa Karakus; Jun Wei

    2005-03-01

    surfaces in-situ; are functionally-graded to give the best combination of thermal, mechanical, and physical properties and chemical stability; or are relatively inexpensive, reliable repair materials. This report covers Task 1.3, Simulative corrosion of candidate materials developed by refractory producers and in the laboratory based on the results of Task 1.1 and Task 1.2. Refractories provided by in-kind sponsors were tested by cup testing, density/porosity determinations, chemical analysis and microscopy. The best performing materials in the cup testing were fused cast materials. However, 2 castables appear to outperforming any of the previously tested materials and may perform better than the fused cast materials in operation. The basis of the high performance of these materials is the low open porosity and permeability to black liquor smelt.

  16. Clinical and radiological features of rheumatoid arthritis in British black Africans.

    Science.gov (United States)

    Ravindran, Vinod; Seah, May-Ai; Elias, David A; Choy, Ernest H; Scott, David L; Gordon, Patrick A

    2008-01-01

    The objective of this study was to determine whether radiographic damage is different in British black African patients with rheumatoid arthritis compared to Caucasian patients. Data on demographics, disease- and disability-related variables were obtained from all black African patients and their age-, gender- and disease-duration-matched Caucasian controls. After all features identifying the patients were concealed, X-rays of hands and feet were scored by using the Sharp/van der Heijde method. Data were analysed using Mann-Whitney U test, t test and chi (2) test. Sixty-four patients (32 in each ethnic group) were studied. The median age was 52 years and median disease duration 6 years. Seventy-two percent of patients were female. Black Africans and Caucasians did not differ significantly in rheumatoid factor positivity, disease-modifying anti-rheumatic drugs and biological treatment use. British black African patients had significantly more tender joints and disability. Joint space narrowing was significantly greater in Caucasian patients [48 (27-85) vs 56 (34-107), p = 0.01]. Caucasian patients had more number of erosions (172 vs 220) and higher erosion score; however, the difference in the erosion scores was not statistically significant [2 (0-48) vs 4.5 (0-46), p = 0.17]. Radiographic damage was less severe in black African patients with rheumatoid arthritis compared to their age-, gender- and disease-duration-matched Caucasian controls. A large prospective study is required to confirm the findings of this study and to establish the factors which might be accountable for any differences in the expression of rheumatoid arthritis in this ethnic group.

  17. UH-60M Black Hawk Helicopter (UH-60M Black Hawk)

    Science.gov (United States)

    2016-12-01

    Selected Acquisition Report (SAR) RCS: DD-A&T(Q&A)823-341 UH-60M Black Hawk Helicopter (UH-60M Black Hawk ) As of FY 2017 President’s Budget Defense...Acquisition Management Information Retrieval (DAMIR) March 21, 2016 18:25:45 UNCLASSIFIED UH-60M Black Hawk December 2015 SAR March 21, 2016 18...Operational Requirements Document OSD - Office of the Secretary of Defense O&S - Operating and Support PAUC - Program Acquisition Unit Cost UH-60M Black Hawk

  18. A Cardy-like formula for rotating black holes with planar horizon

    Energy Technology Data Exchange (ETDEWEB)

    Gaete, Moisés Bravo [Facultad de Ciencias Básicas, Universidad Católica del Maule,Casilla 617, Talca (Chile); Guajardo, Luis; Hassaïne, Mokhtar [Instituto de Matemática y Fisica, Universidad de Talca,Casilla 747, Talca (Chile)

    2017-04-18

    We show that the semiclassical entropy of D−dimensional rotating (an)isotropic black holes with planar horizon can be successfully computed according to a Cardy-like formula. This formula does not refer to any central charges but instead involves the vacuum energy which is identified with a gravitational bulk soliton. The soliton is obtained from the non-rotating black hole solution by means of a double analytic continuation. The robustness of the Cardy-like formula is tested with numerous and varied examples, including AdS, Lifshitz and hyperscaling violation planar black holes.

  19. Black American and Nigerian Pentecostalism: A Black Religious ...

    African Journals Online (AJOL)

    Black American and Nigerian Pentecostalism: A Black Religious Schizophrenia, 1910-2010. ... in American and African Pentecostalism as is related to social crisis, the dislocation of masses brought on by economic deprivation, urbanization, the break up of traditional society and consequence loss of traditional values.

  20. Black Tea

    Science.gov (United States)

    ... mental alertness as well as learning, memory, and information processing skills. It is also used for treating headache; ... of carbamazepine. Since black tea contains caffeine, in theory taking black tea with carbamazepine might decrease the ...

  1. NCLEX-RN Examination Performance by BSN Graduates of Four Historically Black Colleges and Universities

    Science.gov (United States)

    Chesney, Anita M.

    2010-01-01

    This qualitative multiple-case study research explored and described differences as well as NCLEX-RN preparation strategies used by Historically Black College and University (HBCU) baccalaureate nursing programs with consistent NCLEX pass rates versus those with inconsistent pass rates. Two of the four selected programs had a history of consistent…

  2. Use of the radiometric method at creation cell test-systems for pre-screening of anticancer preparations

    International Nuclear Information System (INIS)

    Kuznetsova, N.N.; Khashimova, Z.S.; Sadikov, A.A.

    2004-01-01

    Full text: Development of cancer chemotherapy is tightly bound with investigation of biological activity of different compounds on in vitro test systems. Our research has been directed on definition of sensitivity of the cell line KML removed by us from passed of mice melanoma B-16. We had been investigated action of 18 clinical antineoplastic preparations of different classes: alkylating - sarcolysinum, thiophosphamide, dopan, fhthordopan; antimetabolites - cytararibinum, methotrexatum, 6-mercaptopurinum, 5-fhthorouracilum, fhthorafur; antineoplastic antibiotics- adriamycinum, neomycinum, rubomycinum, bruneomycinum, carminomycinum, olivomycinum; plant substances - vinblastinum, colchaminum (component of ointment which used at treatment of skin cancer) and other - carboplatin. Cytotoxic effect of preparations estimated two methods - radiometric on inclusion of 3H - timidine in cells and spectrophotometric by definition of total amount nucleic acids and protein. For this purpose KML cells passed in quantity of 120 thousand in 3 ml of nutrient medium RPMI 1640, 10 % calf embryo serum in bottles and after 24 hours entered substances in dozes from 0,01 up to 100 μg/ml. Contact of substances to cells was 24 hours, then 10 μ Ci 3 H - timidine was injected on bottles at 1 hour. Cells transferred on GFC-filters, washed from not connected label. Filters transferred in scintillation liquid and a level of a radio-activity determined on β-counter. All tested clinical preparations appeared active within the criteria of activity, thus the radiometric method was more sensitive, than spectrophotometric. Thus, testing results of model have shown that stable cell line KML was sensitive to action of 18 clinical preparations with various mechanisms of action by different estimations of damaging action. This model can be used for biological activity of new potential cancerolytics pre-screening. This work was supported by the Center of Science and Technology of the Republic of

  3. Steps Leading to an Ethnographic Analysis of Mothers Preparing Children for a Memory Test.

    Science.gov (United States)

    Rogoff, Barbara; Gardner, William P.

    In this study four research strategies used in previous studies of the socialization of cognitive skills were first contrasted and then assessed in terms of five criteria. (The data base for this study was 32 videotapes of mothers preparing their 7- or 9-year-old children to take a memory test.) The four strategies (frequency coding, fine-grained…

  4. Test Preparation: Your Role

    Science.gov (United States)

    ... eating cooked meat may be required since some studies have shown that eating cooked meat prior to testing can temporarily increase the level of creatinine. Fecal occult blood test : certain food and/or medication restrictions may be required. Urine ...

  5. I'm a Jesus girl: coping stories of Black American women diagnosed with breast cancer.

    Science.gov (United States)

    Gregg, Godfrey

    2011-12-01

    Breast cancer continues to be the most diagnosed cancer for all women, excluding non-melanoma skin cancer, in the United States. Incidence rates are 1 in 8 for an American woman being diagnosed. Moreover, statistics indicate that every 13 min an American woman dies from complications related to breast cancer. Despite all the gains made in the area of cancer research, Black American women continue to have a 67% higher mortality rate than their White counterparts. There is no preparation for a diagnosis of breast cancer. Upon hearing the words: you have breast cancer, a woman's life is forever altered. The woman's initial reactions of denial and/or anger yield to strategic responses. These responses may strengthen the woman's resiliency both during and following treatments. Research indicates that Black Americans, specifically Black American women, exhibit greater religiosity/spirituality than do other racial/ethnic groups. In addition, the use of religiosity/spirituality by Black Americans increases during a crisis. This qualitative study examines how religiosity/spirituality was utilized as a coping mechanism by a group of Black American women following their diagnoses of breast cancer.

  6. Exponential fading to white of black holes in quantum gravity

    International Nuclear Information System (INIS)

    Barceló, Carlos; Carballo-Rubio, Raúl; Garay, Luis J

    2017-01-01

    Quantization of the gravitational field may allow the existence of a decay channel of black holes into white holes with an explicit time-reversal symmetry. The definition of a meaningful decay probability for this channel is studied in spherically symmetric situations. As a first nontrivial calculation, we present the functional integration over a set of geometries using a single-variable function to interpolate between black-hole and white-hole geometries in a bounded region of spacetime. This computation gives a finite result which depends only on the Schwarzschild mass and a parameter measuring the width of the interpolating region. The associated probability distribution displays an exponential decay law on the latter parameter, with a mean lifetime inversely proportional to the Schwarzschild mass. In physical terms this would imply that matter collapsing to a black hole from a finite radius bounces back elastically and instantaneously, with negligible time delay as measured by external observers. These results invite to reconsider the ultimate nature of astrophysical black holes, providing a possible mechanism for the formation of black stars instead of proper general relativistic black holes. The existence of both this decay channel and black stars can be tested in future observations of gravitational waves. (paper)

  7. Tracing Supermassive Black Hole Growth with Offset and Dual AGN

    Science.gov (United States)

    Comerford, Julia

    The growth of supermassive black holes is tied to the evolution of their host galaxies, but we are still missing a fundamental understanding of how and when supermassive black holes build up their mass. Black hole mass growth can be traced when the black holes are powered as active galactic nuclei (AGN), and AGN activity can be triggered by the stochastic accretion of gas or by gas inflows driven by galaxy mergers. Galaxy merger simulations make a series of predictions about the AGN that are triggered by mergers: (1) major mergers preferentially trigger higher-luminosity AGN, (2) minor mergers more often trigger AGN activity in one supermassive black hole while major mergers more often trigger AGN activity in both black holes in a merger, and (3) black hole mass growth peaks when the black holes approach the center (theory have been limited by the difficulty in defining a clean observational sample of AGN in galaxy mergers and the observational challenge of spatially resolving two AGN with small (dual AGN as a new observational tool that can be used to address how and when supermassive black hole mass growth occurs. A merger of two galaxies brings two supermassive black holes together, and the two black holes exist at kpc-scale separations for 100 Myr before ultimately merging. While the black holes are at kpc-scale separations, they are known as dual AGN when both of them are fueled as AGN and offset AGN when only one is fueled as an AGN. Since offset and dual AGN only occur in galaxy mergers, by their very definition, they provide a clean observational sample of black hole mass growth in galaxy mergers. The small, kpc-scale separations of offset and dual AGN also enable an observational test of black hole fueling near the centers of merger-remnant galaxies. The full potential of offset and dual AGN for such studies of black hole mass growth has not yet been realized, due to the small number of such systems known. To date, only 13 confirmed offset and dual AGN are

  8. Primary vesicoureteral reflux in Blacks with posterior urethral valves: Does it occur?

    International Nuclear Information System (INIS)

    Nancarrow, P.A.; Lebowitz, R.L.

    1988-01-01

    Primary vesicoureteral reflux (VUR) is thought to be largely independent of obstruction. Therefore, in patients with urethral obstruction due to posterior urethral valves (PUV) the occurrence of VUR is coincidental. In addition, primary VUR is reported to be uncommon in black children. If these two premises are correct, then primary VUR should be rare in black males with PUV. To test this hypothesis, we reviewed the medical records and radiographs of 43 males with PUV. Twenty-one of the 37 non-black males with PUV had VUR, of which 67% was primary and 33% was secondary. Three of the six Blacks with PUV had VUR of which none was primary and all was secondary. Thus, Blacks with PUV lend credence to the theory that primary VUR is not caused by obstruction and support the observation that primary VUR is rare in black children, even those with PUV. (orig.)

  9. The relationships among Black consciousness, self-esteem, and academic self-efficacy in African American men.

    Science.gov (United States)

    Okech, Allan Prince; Harrington, Rick

    2002-03-01

    The purpose of this study was to investigate the relationships among Black consciousness, self-esteem, and academic self-efficacy in African American men. The participants were 120 African American male college students at a predominantly African American university. The authors administered 3 instruments--the Developmental Inventory of Black Consciousness (DIB-C; J. Milliones, 1980), the M. Rosenberg (1965) Self-Esteem Scale, and R. E. Wood and E. A. Locke's (1987) Academic Self-Efficacy Scale--to test the hypotheses. They used an independent-measures t test and a Pearson r correlation to analyze the data. The results of the study supported the hypotheses under investigation. Significant positive relationships were found between Black consciousness and self-esteem and Black consciousness and academic self-efficacy. The results of the study showed that Black consciousness appears to be an important construct to use in understanding self-esteem and academic self-efficacy in African American men.

  10. COLLECTIVE LEADERSHIP: A Case Study of the All Blacks

    OpenAIRE

    Thomas Johnson; Andrew J Martin; Farah R Palmer; Geoffrey Watson; Phil Ramsey

    2012-01-01

    This case study evaluates the development of a formal collective leadership approach by the All Blacks (New Zealand’s national men’s rugby team) management. The All Blacks have an astonishing 75% winning record in test matches over a hundred year period. This winning ethos is part of their organizational culture, which has been developed, nurtured and sustained since the inception of the first national team in 1903 (Palenski, 2003; Tobin, 2005). In this qualitative research study, primary ...

  11. Black shale studies in Kentucky. Annual report, October 1, 1977--September 30, 1978

    Energy Technology Data Exchange (ETDEWEB)

    Blackburn, W.H. (comp.)

    1978-01-01

    Black shale studies have focussed on their geochemistry, stratigraphy, and subsurface characterization, and on the compilation of an archive of cored material. Technical progress made in these areas are reported. In addition, two Master's theses prepared under the stratigraphic study project and one under the geochemical study project are included and are abstracted and indexed separately. (JSR)

  12. Black holes are warm

    International Nuclear Information System (INIS)

    Ravndal, F.

    1978-01-01

    Applying Einstein's theory of gravitation to black holes and their interactions with their surroundings leads to the conclusion that the sum of the surface areas of several black holes can never become less. This is shown to be analogous to entropy in thermodynamics, and the term entropy is also thus applied to black holes. Continuing, expressions are found for the temperature of a black hole and its luminosity. Thermal radiation is shown to lead to explosion of the black hole. Numerical examples are discussed involving the temperature, the mass, the luminosity and the lifetime of black mini-holes. It is pointed out that no explosions corresponding to the prediction have been observed. It is also shown that the principle of conservation of leptons and baryons is broken by hot black holes, but that this need not be a problem. The related concept of instantons is cited. It is thought that understanding of thermal radiation from black holes may be important for the development of a quantified gravitation theory. (JIW)

  13. Is It because I'm Black? A Black Female Research Experience

    Science.gov (United States)

    Maylor, Uvanney

    2009-01-01

    This article examines what it means to be a Black female researcher in contemporary Britain. Drawing on Black feminist theory and critical race theory (CRT), this article seeks to highlight some of the experiences and challenges that Black female researchers face when undertaking research, particularly research that has diversity, equality or…

  14. Imaging a non-singular rotating black hole at the center of the Galaxy

    Science.gov (United States)

    Lamy, F.; Gourgoulhon, E.; Paumard, T.; Vincent, F. H.

    2018-06-01

    We show that the rotating generalization of Hayward’s non-singular black hole previously studied in the literature is geodesically incomplete, and that its straightforward extension leads to a singular spacetime. We present another extension, which is devoid of any curvature singularity. The obtained metric depends on three parameters and, depending on their values, yields an event horizon or not. These two regimes, named respectively regular rotating Hayward black hole and naked rotating wormhole, are studied both numerically and analytically. In preparation for the upcoming results of the Event Horizon Telescope, the images of an accretion torus around Sgr A*, the supermassive object at the center of the Galaxy, are computed. These images contain, even in the absence of a horizon, a central faint region which bears a resemblance to the shadow of Kerr black holes and emphasizes the difficulty of claiming the existence of an event horizon from the analysis of strong-field images. The frequencies of the co- and contra-rotating orbits at the innermost stable circular orbit (ISCO) in this geometry are also computed, in the hope that quasi-periodic oscillations may permit to compare this model with Kerr’s black hole on observational grounds.

  15. Seroprevalence of Toxoplasma gondii and Trichinella spiralis in North Carolina black bears (Ursus americanus).

    Science.gov (United States)

    Nutter, F B; Levine, J F; Stoskopf, M K; Gamble, H R; Dubey, J P

    1998-10-01

    Serum samples from 143 hunter-killed black bears were collected during the 1996 and 1997 black bear hunting seasons in eastern North Carolina. All samples were tested for antibodies to Toxoplasma gondii by the modified agglutination test. Antibodies to T. gondii were present in 120 of 143 (84%) bears. Females had significantly higher titers than males (Wilcoxon rank sums test, P = 0.045), and titers increased with age (Jonckheere test, P = 0.01). Samples collected during 1996 (n = 79) were tested for antibodies to Trichinella spiralis by enzyme-linked immunosorbent assay. No samples were positive for antibodies to T. spiralis.

  16. Numerical study of nonspherical black hole accretion

    International Nuclear Information System (INIS)

    Hawley, J.F.

    1984-01-01

    This thesis describes in detail a two-dimensional, axisymmetric computer code for calculating fully relativistic ideal gas hydrodynamics around a Kerr black hole. The aim is to study fully dynamic inviscid fluid accretion onto black holes, as well as to study the evolution and development of nonlinear instabilities in pressure supported accretion disks. In order to fully calibrate and document the code, certain analytic solutions for shock tubes and special accretion flows are derived; these solutions form the basis for code testing. The numerical techniques used are developed and discussed. A variety of alternate differencing schemes are compared on an analytic test bed. Some discussion is devoted to general issues in finite differencing. The working code is calibrated using analytically solvable accretion problems, including the radial accretion of dust and of fluid with pressure (Bondi accretion). Two dimensional test problems include the spiraling infall of low angular momentum fluid, the formation of a pressure supported torus, and the stable evolution of a torus. A series of numerical models are discussed and illustrated with selected plots

  17. Nanoparticles Ni electroplating and black paint for solar collector applications

    Directory of Open Access Journals (Sweden)

    J. El Nady

    2016-06-01

    Full Text Available A nanoparticles layer of bright nickel base was deposited on copper substrates using electrodeposition technique before spraying the paint. IR reflectance of the paint was found to be around 0.4 without bright nickel layer and the reflectance increased to 0.6 at a Ni layer thickness of 750 nm. The efficiency of the constructed solar collectors using black paint and black paint combined with bright nickel was found to be better than black paint individually. After aging tests under high temperature, Bright nickel improved the stability of the absorber paint. The collector optical gain FR(τα was lowered by 24.7% for the commercial paint and lowered by 19.3% for the commercial paint combined with bright nickel. The overall heat loss FR(UL was increased by 3.3% for the commercial paint and increased by 2.7% for the commercial paint combined with bright nickel after the temperature aging test.

  18. Massive Binary Black Holes in the Cosmic Landscape

    Science.gov (United States)

    Colpi, Monica; Dotti, Massimo

    2011-02-01

    Binary black holes occupy a special place in our quest for understanding the evolution of galaxies along cosmic history. If massive black holes grow at the center of (pre-)galactic structures that experience a sequence of merger episodes, then dual black holes form as inescapable outcome of galaxy assembly, and can in principle be detected as powerful dual quasars. But, if the black holes reach coalescence, during their inspiral inside the galaxy remnant, then they become the loudest sources of gravitational waves ever in the universe. The Laser Interferometer Space Antenna is being developed to reveal these waves that carry information on the mass and spin of these binary black holes out to very large look-back times. Nature seems to provide a pathway for the formation of these exotic binaries, and a number of key questions need to be addressed: How do massive black holes pair in a merger? Depending on the properties of the underlying galaxies, do black holes always form a close Keplerian binary? If a binary forms, does hardening proceed down to the domain controlled by gravitational wave back reaction? What is the role played by gas and/or stars in braking the black holes, and on which timescale does coalescence occur? Can the black holes accrete on flight and shine during their pathway to coalescence? After outlining key observational facts on dual/binary black holes, we review the progress made in tracing their dynamics in the habitat of a gas-rich merger down to the smallest scales ever probed with the help of powerful numerical simulations. N-Body/hydrodynamical codes have proven to be vital tools for studying their evolution, and progress in this field is expected to grow rapidly in the effort to describe, in full realism, the physics of stars and gas around the black holes, starting from the cosmological large scale of a merger. If detected in the new window provided by the upcoming gravitational wave experiments, binary black holes will provide a deep view

  19. Reading Comprehension in Test Preparation Classes: An Analysis of Teachers' Pedagogical Content Knowledge in TESOL

    Science.gov (United States)

    Irvine-Niakaris, Christine; Kiely, Richard

    2015-01-01

    This article examines the pedagogical content knowledge which underpins the practices in reading lessons of experienced teachers in test preparation classes. It takes as a starting point the assumption that practice is shaped by teacher cognitions, which are established through professional training and classroom experience. Thus, the study…

  20. The stable problem of the black-hole connected region in the Schwarzschild black hole

    OpenAIRE

    Tian, Guihua

    2005-01-01

    The stability of the Schwarzschild black hole is studied. Using the Painlev\\'{e} coordinate, our region can be defined as the black-hole-connected region(r>2m, see text) of the Schwarzschild black hole or the white-hole-connected region(r>2m, see text) of the Schwarzschild black hole. We study the stable problems of the black-hole-connected region. The conclusions are: (1) in the black-hole-connected region, the initially regular perturbation fields must have real frequency or complex frequen...

  1. Quantum aspects of black holes

    CERN Document Server

    2015-01-01

    Beginning with an overview of the theory of black holes by the editor, this book presents a collection of ten chapters by leading physicists dealing with the variety of quantum mechanical and quantum gravitational effects pertinent to black holes. The contributions address topics such as Hawking radiation, the thermodynamics of black holes, the information paradox and firewalls, Monsters, primordial black holes, self-gravitating Bose-Einstein condensates, the formation of small black holes in high energetic collisions of particles, minimal length effects in black holes and small black holes at the Large Hadron Collider. Viewed as a whole the collection provides stimulating reading for researchers and graduate students seeking a summary of the quantum features of black holes.

  2. Is black-hole ringdown a memory of its progenitor?

    Science.gov (United States)

    Kamaretsos, Ioannis; Hannam, Mark; Sathyaprakash, B S

    2012-10-05

    We perform an extensive numerical study of coalescing black-hole binaries to understand the gravitational-wave spectrum of quasinormal modes excited in the merged black hole. Remarkably, we find that the masses and spins of the progenitor are clearly encoded in the mode spectrum of the ringdown signal. Some of the mode amplitudes carry the signature of the binary's mass ratio, while others depend critically on the spins. Simulations of precessing binaries suggest that our results carry over to generic systems. Using Bayesian inference, we demonstrate that it is possible to accurately measure the mass ratio and a proper combination of spins even when the binary is itself invisible to a detector. Using a mapping of the binary masses and spins to the final black-hole spin allows us to further extract the spin components of the progenitor. Our results could have tremendous implications for gravitational astronomy by facilitating novel tests of general relativity using merging black holes.

  3. How to prepare water accommodated fractions from petroleum hydrocarbons for use in aquatic toxicity testing - the basics

    International Nuclear Information System (INIS)

    Blenkinsopp, S.; Boileau, P.; Kyle, D.; Sergy, G.; Fingas, M.

    1996-01-01

    A method to prepare water accommodated fractions (WAFs) from petroleum products for use in toxicity testing, was introduced. In order to develop a repeatable protocol, a systematic study of a range of experimental variables was conducted. One semi-solid oil and six liquid oils were exposed to artificial seawater. Studies were also performed on three liquid oils exposed to freshwater. Low energy mixing and fluorinated Nalgene carboys was used to produce the WAFs. The mixing time depended on the oil type and loading rate. Individual loading rates were prepared for each concentration, because WAF composition is influenced by loading rate rather than serial dilution. An overview of the basic concepts of WAF preparation was described. A draft protocol for preparing WAFs from liquid and semi-solid oil was also described and results were summarized. 5 refs., 3 tabs., 6 figs

  4. 3 CFR 8404 - Proclamation 8404 of August 30, 2009. National Historically Black Colleges and Universities Week...

    Science.gov (United States)

    2010-01-01

    ..., to the growth of local communities, and to our Nation's overall economy. This week, we celebrate the... new, innovative, and ambitious strategies to help the next generation of Americans successfully complete college and prepare themselves for the global economy. During National Historically Black Colleges...

  5. Some aspects of preparation and testing of group constants group constant system ABBN-90

    International Nuclear Information System (INIS)

    Nikolaev, M.N.; Tsiboulia, A.M.; Manturov, G.N.

    1996-01-01

    This paper presents an overview of activities performed to prepare and test the group constants ABBN-90. The ABBN-90 set is designed for application calculations of fast, intermediate and thermal nuclear reactors. The calculations of subgroup parameters are discussed. The processing code system GRUCON is mentioned in comparison to the NJOY code system. Proposals are made for future activities. (author). Figs, tabs

  6. Merger transitions in brane-black-hole systems: Criticality, scaling, and self-similarity

    International Nuclear Information System (INIS)

    Frolov, Valeri P.

    2006-01-01

    We propose a toy model for studying merger transitions in a curved spacetime with an arbitrary number of dimensions. This model includes a bulk N-dimensional static spherically symmetric black hole and a test D-dimensional brane (D≤N-1) interacting with the black hole. The brane is asymptotically flat and allows a O(D-1) group of symmetry. Such a brane-black-hole (BBH) system has two different phases. The first one is formed by solutions describing a brane crossing the horizon of the bulk black hole. In this case the internal induced geometry of the brane describes a D-dimensional black hole. The other phase consists of solutions for branes which do not intersect the horizon, and the induced geometry does not have a horizon. We study a critical solution at the threshold of the brane-black-hole formation, and the solutions which are close to it. In particular, we demonstrate that there exists a striking similarity of the merger transition, during which the phase of the BBH system is changed, both with the Choptuik critical collapse and with the merger transitions in the higher dimensional caged black-hole-black-string system

  7. Interactions of black cohosh, a traditional herbal medicine, with therapy for breast cancer

    International Nuclear Information System (INIS)

    Rockwell, S.; Liu, Y.; Higgins, S.A.

    2003-01-01

    Herbal medicines based on extracts of Cimicifuga racemosa (black cohosh) are widely used by breast cancer patients, but the effects of these extracts have not been rigorously studied. We examined the effects of standardized commercial extracts of black cohosh on the cytotoxicity of radiation, Adriamycin, Taxotere, and Cisplatin to breast cancer cells in vitro. Exponentially growing cultures of EMT6 mouse mammary tumor cells were exposed to black cohosh extracts continuously for 24 h, beginning 4 hours before irradiation or the 2 h drug treatment. Full dose-response curves were determined for radiation and for each drug under three conditions: alone, in combination with black cohosh extract, and in combination with the vehicle used to prepare the extract. Cell survival was assayed using a colony formation assay. The herbal extracts alone had no significant effect on the growth or viability of these breast cancer cells. The effects of the extracts on the outcome of treatment varied with the treatment agent. Black cohosh protected cells slightly from Cisplatin, had no effect on the dose-response curve for radiation, and sensitized cells to Adriamycin and Taxotere. The vehicle had no discernable effect. These findings show that black cohosh extracts are not simply 'harmless herbs' that can be ignored by physicians treating cancer patients, but instead contain active agents which can modulate the effects of therapy with conventional therapeutic agents. Further cell culture studies are needed to determine the mechanism underlying this effect. Studies with tumors and normal tissues in mice are needed to assess whether black cohosh extracts alter the effectiveness of radiation and drugs in treating breast cancer or alter the toxicities of these therapies

  8. Preparation of demipermanent and semipermanent hair dyes gels from ethanol extract of Caesalpinia sappan L. using carbomer as gelling agent

    Science.gov (United States)

    Indrawati, T.; Syahrin, A.; Irpan

    2017-07-01

    Caesalpinia sappan L. (Cs L) contains of essential oils, saponin, brazilin, brazilein, alkaloids, flavonoids and tannins that have a function as cationic natural dyes. The aim of this research was to prepare the ethanol extract of Cs L wood and to prepare demi-permanent and semi-permanent of hair dye gels by using Carbomer of 2 % and 1.5 % as gelling agent and Cs L extract as cationic dyes. The Extract of Cs L was macerated by using ethanol of 96 % as the solvent, and then thickened. Three formula of demi-permanent hair dye gels were made by using Cs L extract of 3 %, 6% and 9 %. Three formula of semi-permanent hair dye gels were made by using Cs L extract of 2.50 %, 7.00 % and 10.50 %. Those hair dyes gels were prepared by swelling and mixing methods. All products of hair dyes gels were evaluated with organoleptic test, homogeneity test, pH test, consistency test, rheological properties test and dyeing effect test. The demi-permanent hair dye gels products had brown to brown dark black colors, pH of 5.05-5.43, homogeny, specific Cs L odor, and had pseudoplastic thixotropic flow characteristic. The semi-permanent hair dye gels products had red color pH of 6.5-6.25, homogeny, Cs L odor, and have pseudoplastic thixotropic flow characteristics. The optimum formula of demi-permanent was formula gel that contained of 6 % extract of Cs L and the optimum formula of permanent hair dyes gel was formula that contained of 10.50 % extract of Cs L.

  9. Black holes and beyond

    Energy Technology Data Exchange (ETDEWEB)

    NONE

    2002-02-01

    Belief in the existence of black holes is the ultimate act of faith for a physicist. First suggested by the English clergyman John Michell in the year 1784, the gravitational pull of a black hole is so strong that nothing - not even light - can escape. Gravity might be the weakest of the fundamental forces but black-hole physics is not for the faint-hearted. Black holes present obvious problems for would-be observers because they cannot, by definition, be seen with conventional telescopes - although before the end of the decade gravitational-wave detectors should be able to study collisions between black holes. Until then astronomers can only infer the existence of a black hole from its gravitational influence on other matter, or from the X-rays emitted by gas and dust as they are dragged into the black hole. However, once this material passes through the 'event horizon' that surrounds the black hole, we will never see it again - not even with X-ray specs. Despite these observational problems, most physicists and astronomers believe that black holes do exist. Small black holes a few kilometres across are thought to form when stars weighing more than about two solar masses collapse under the weight of their own gravity, while supermassive black holes weighing millions of solar masses appear to be present at the centre of most galaxies. Moreover, some brave physicists have proposed ways to make black holes - or at least event horizons - in the laboratory. The basic idea behind these 'artificial black holes' is not to compress a large amount of mass into a small volume, but to reduce the speed of light in a moving medium to less than the speed of the medium and so create an event horizon. The parallels with real black holes are not exact but the experiments could shed new light on a variety of phenomena. The first challenge, however, is to get money for the research. One year on from a high-profile meeting on artificial black holes in London, for

  10. Complicated Contradictions Amid Black Feminism and Millennial Black Women Teachers Creating Curriculum for Black Girls

    Science.gov (United States)

    Nyachae, Tiffany M.

    2016-01-01

    Millennial Black women teachers wrestle with two simultaneous burdens: disrupting the racist and sexist status quo of schooling through curriculum, and employing tactics to survive school politics among their majority White women colleagues. This article describes how the "Sisters of Promise" (SOP) curriculum aligned with Black feminism…

  11. Development of a water-soluble preparation of emamectin benzoate and its preventative effect against the wilting of pot-grown pine trees inoculated with the pine wood nematode, Bursaphelenchus xylophilus.

    Science.gov (United States)

    Takai, K; Soejima, T; Suzuki, T; Kawazu, K

    2001-05-01

    Water-soluble preparations have been investigated to develop a trunk injection agent based on the poorly water-soluble anti-nematode emamectin benzoate. Following tests on the phytotoxicity of some solvents and solubilizers and demonstration of the ability of some solubilizers to dissolve emamectin benzoate in water, acetone + methanol was selected as the solvent and Polysorbate 80 as the solubilizer. This water-soluble preparation of emamectin benzoate prevented the wilting of pot-grown 4-year-old trees of the Japanese black pine, Pinus thunbergii, artificially inoculated with the pine wood nematode, Bursaphelenchus xylophilus, at a dose of 20 g emamectin benzoate per cubic metre of pine tree.

  12. Black hole-galaxy co-evolution in the Mufasa simulations

    Science.gov (United States)

    Dave, Romeel; Angles-Alcazar, Daniel

    2017-08-01

    The Mufasa simulations are large-scale cosmological and zoom simulations of galaxy formation that employ novel state of the art modules for star formation and feedback physics, resulting in very good agreement with many key galaxy observables over most of cosmic time. We have recently included black hole growth and feedback using the torque-limited accretion model, which has several advantages over the commonly-used Bondi accretion. We also include AGN feedback using a BAL mode at high Eddington rates and low black hole masses, and a jet mode at low Eddington rates that successfully quenches galaxies. In this talk I will describe preliminary results of the AGN population and its evolution over cosmic time within our new simulations, including cosmological simulations of the general black hole population as well as zoom simulations targeting massive galaxies, with a focus on understanding the co-growth of black holes and galaxies as a function of mass, environment, and cosmic epoch. I will also discuss multi-wavelength approaches to testing and constraining our black hole model in particular using upcoming X-ray and radio facilities such as Lynx and the SKA.

  13. Biological control of banana black Sigatoka disease with Trichoderma

    OpenAIRE

    Poholl Adan Sagratzki Cavero; Rogério Eiji Hanada; Luadir Gasparotto; Rosalee Albuquerque Coelho Neto; Jorge Teodoro de Souza

    2015-01-01

    Black Sigatoka disease caused by Mycosphaerella fijiensis is the most severe banana disease worldwide. The pathogen is in an invasive phase in Brazil and is already present in most States of the country. The potential of 29 isolates of Trichoderma spp. was studied for the control of black Sigatoka disease under field conditions. Four isolates were able to significantly reduce disease severity and were further tested in a second field experiment. Isolate 2.047 showed the best results in both f...

  14. A community-based trial of educational interventions with fecal immunochemical tests for colorectal cancer screening uptake among blacks in community settings.

    Science.gov (United States)

    Christy, Shannon M; Davis, Stacy N; Williams, Kimberly R; Zhao, Xiuhua; Govindaraju, Swapomthi K; Quinn, Gwendolyn P; Vadaparampil, Susan T; Lin, Hui-Yi; Sutton, Steven K; Roethzeim, Richard R; Shibata, David; Meade, Cathy D; Gwede, Clement K

    2016-11-15

    Intervention studies among individuals in diverse community settings are needed to reduce health disparities in colorectal cancer (CRC) screening and mortality rates. The current study compared the efficacy of 2 intervention conditions promoting CRC screening among black individuals. Black individuals ages 50 to 75 years (N = 330) were recruited in community settings in 4 Tampa Bay counties. After obtaining consent and conducting a baseline interview to assess sociodemographic and health-related variables, participants received either a culturally targeted CRC photonovella booklet plus a fecal immunochemical test (FIT) kit or a standard CRC screening brochure plus an FIT kit. The primary outcome was FIT kit screening uptake. FIT screening uptake at 6 months was 86.7% overall (90.3% in the brochure group and 81.9% in the photonovella group). Controlling for baseline between-group differences, there was no influence of intervention on FIT kit uptake (P = .756). Significant predictors of not returning an FIT kit included being unable to work (P = .010), having higher religious belief scores (P = .015), and living farther from the cancer center (P = .015). Providing FIT kits and educational print materials to black individuals in community settings resulted in high rates of CRC screening. The study also identified subgroups of participants who were less likely to return an FIT kit and provides insight for future interventions. Cancer 2016;122:3288-3296. © 2016 American Cancer Society. © 2016 American Cancer Society.

  15. Rotating black holes at future colliders. III. Determination of black hole evolution

    International Nuclear Information System (INIS)

    Ida, Daisuke; Oda, Kin-ya; Park, Seong Chan

    2006-01-01

    TeV scale gravity scenario predicts that the black hole production dominates over all other interactions above the scale and that the Large Hadron Collider will be a black hole factory. Such higher-dimensional black holes mainly decay into the standard model fields via the Hawking radiation whose spectrum can be computed from the greybody factor. Here we complete the series of our work by showing the greybody factors and the resultant spectra for the brane-localized spinor and vector field emissions for arbitrary frequencies. Combining these results with the previous works, we determine the complete radiation spectra and the subsequent time evolution of the black hole. We find that, for a typical event, well more than half a black hole mass is emitted when the hole is still highly rotating, confirming our previous claim that it is important to take into account the angular momentum of black holes

  16. Effect of heat treatment, top coatings and conversion coatings on the corrosion properties of black electroless Ni-P films

    Energy Technology Data Exchange (ETDEWEB)

    Liu, Y., E-mail: liu_yunli@hotmail.com [R and D Department, MacDermid plc, 198 Golden Hillock Road, Birmingham B11 2PN (United Kingdom); Beckett, D.; Hawthorne, D. [R and D Department, MacDermid plc, 198 Golden Hillock Road, Birmingham B11 2PN (United Kingdom)

    2011-02-15

    Electroless black nickel-phosphorus plating is an advanced electroless nickel plating process formulated to deposit a black finish when processed through an oxidizing acid solution. Heat treatment, five types of top organic coating techniques and one conversion coating technique with three different experimental conditions were investigated to stabilize the black film and increase the hardness and corrosion resistance. Morphology and compositions of electroless nickel-phosphorous films with or without heat treatment, with five types of top organic coatings, and with three conversion coatings were compared to examine nickel, phosphorus, oxygen, carbon, silicon and chrome contents on the corrosion resistance of black surfaces by energy dispersive X-ray microanalysis and scanning electron microscope. Corrosion resistance of black electroless nickel-phosphorus coatings with or without heat treatment, with five types of top organic coatings, and with three conversion coatings was investigated by the polarization measurements and the salt spray test in 5% NaCl solution, respectively. HydroLac as the top organic coating from MacDermid showed the excellent corrosion resistance and the black EN film did not lose the black color after 48 h salt spray test. Electrotarnil B process with 0.5 ASD for 1 min stabilized the black Ni-P film immediately and increased the hardness and corrosion performance of the black Ni-P film. The black Ni-P coating with Electroarnil B process passed the 5% NaCl salt spray test for 3000 h in the black color and had a minimal corrosion current 0.8547 {mu}A/cm{sup 2} by the polarization measurement.

  17. Cryopreservation of spermatozoa of black marlin, Makaira indica (Teleostei: Istiophoridae).

    Science.gov (United States)

    van der Straten, K M; Leung, L K-P; Rossini, R; Johnston, S D

    2006-01-01

    As a first step towards the development of a method for the cryopreservation of black marlin spermatozoa, this study investigated the effect of dimethylsulfoxide (DMSO) concentration and pellet size on post-thaw spermatozoal motility. Spermatozoa were recovered from the spermatic duct of testes retrieved post-mortem from four adult black marlin caught in the Coral Sea spawning grounds of Australia. Undiluted spermatozoa were stored on ice for 4 to 10 hours during transport to shore, then evaluated for motility after activation in seawater (1:10 v:v). Spermatozoa were prepared for cryopreservation in pellets by extension (1:3 v:v) in a defined fish Ringer's solution to give two final DMSO concentrations of 2.5% or 5.0%. Diluted spermatozoa were frozen directly on a dry ice block in pellet sizes of either 0.25 ml or 0.50 ml. Frozen pellets were thawed in a water bath at 40 degrees C for 60 seconds and assessed for post-thaw motility following activation in seawater. Spermatozoa recovered within 50 minutes of death and chilled on ice for 4 to 10 hours showed a mean (+/- SEM) motility immediately following activation of 91.6 +/- 7.9%. 50% of the spermatozoa remained motile for approximately 4 to 5 minutes. Following cryopreservation, mean motility declined significantly across all cryoprotectant and pellet size combinations (P < 0.001) but spermatozoa frozen in 2.5% DMSO showed higher motility than those frozen in 5.0% DMSO (P = 0.014). Pellet size had no effect on post-thaw motility (P = 0.179).

  18. Preparation and characterization of flake graphite/silicon/carbon spherical composite as anode materials for lithium-ion batteries

    Energy Technology Data Exchange (ETDEWEB)

    Lai Jun [School of Metallurgical Science and Engineering, Central South University, Changsha 410083 (China); Guo Huajun, E-mail: Lai_jun_@126.com [School of Metallurgical Science and Engineering, Central South University, Changsha 410083 (China); Wang Zhixing; Li Xinhai; Zhang Xiaoping; Wu Feixiang; Yue Peng [School of Metallurgical Science and Engineering, Central South University, Changsha 410083 (China)

    2012-07-25

    Highlights: Black-Right-Pointing-Pointer Flake graphite/silicon/carbon composite is synthesized via spray drying. Black-Right-Pointing-Pointer Flake graphite of {approx}0.5 {mu}m and glucose are used to prepare the composite. Black-Right-Pointing-Pointer The as-prepared composite shows spherical and porous appearance. Black-Right-Pointing-Pointer The composite shows nearly the same cycleability as commercial graphite in 20 cycles. Black-Right-Pointing-Pointer The composite shows a reversible capacity of 552 mAh/g at the 20th cycle. - Abstract: Using nano-Si, glucose and flake graphite of {approx}0.5 {mu}m as raw materials, flake graphite/silicon/carbon composite is successfully synthesized via spray drying and subsequent pyrolysis. The samples are characterized by XRD, SEM, TEM and electrochemical measurements. The composite is composed of flake graphite, nano-Si and amorphous glucose-pyrolyzed carbon and presents good spherical appearance. Some micron pores arising from the decomposition of glucose exist on the surface of the composite particles. The composite has a high reversible capacity of 602.7 mAh/g with an initial coulombic efficiency of 69.71%, and shows nearly the same cycleability as the commercial graphite in 20 cycles. Both the glucose-pyrolyzed carbon and the micron pores play important roles in improving the cycleability of the composite. The flake graphite/silicon/carbon composite electrode is a potential alternative to graphite for high energy-density lithium ion batteries.

  19. The Mind as Black Box: A Simulation of Theory Building in Psychology.

    Science.gov (United States)

    Hildebrandt, Carolyn; Oliver, Jennifer

    2000-01-01

    Discusses an activity that uses the metaphor "the mind is a black box," in which students work in groups to discover what is inside a sealed, black, plastic box. States that the activity enables students to understand the need for theories in psychology and to comprehend how psychologists build, test, and refine those theories. (CMK)

  20. Study of tribological properties of natural rubber containing carbon nanotubes and carbon black as hybrid fillers

    Science.gov (United States)

    Harea, Evghenii; Stoček, Radek; Storozhuk, Liudmyla; Sementsov, Yurii; Kartel, Nikolai

    2018-04-01

    Dry friction and wear properties of natural rubber (NR), containing multi-walled carbon nanotubes (MWCNT) and carbon black (CB), were investigated. Natural rubber (NR)-based composites containing all common additives and curatives, and a fixed amount (30 phr—parts per 100 rubber by weight) of hybrid fillers (MWCNT x + CB30-x ) were prepared by simple mixing procedure and tested. The main goal was to study the behaviours of composites at different tribological testing conditions, such as friction speed and normal load. It was found that with an increase of concentration of MWCNT from x = 0 phr to x = 5 phr in studied composites, there was a decrease in the coefficient of friction (COF) with no significant change in wear in the framework of each used combination of testing parameters. Generally, higher friction speed at certain normal force led to the increase of COF of all the samples and wear reflected deliberate value fluctuation. Also, it was established that considerable growth of wear and unexpected reducing of friction coefficient ensued from increasing of applied load for every fixed sliding speed.

  1. Support for harmful treatment and reduction of empathy toward blacks: "Remnants" of stereotype activation involving Hurricane Katrina and "Lil' Kim"

    NARCIS (Netherlands)

    Johnson, J.D.; Bushman, B.J.

    2008-01-01

    Two experiments involving White participants tested the influence of media-based Black stereotypes on subsequent responses to Black and White persons-in-need. Experiment 1 showed that priming the "Black criminal" stereotype through exposure to photographs of Blacks looting after Hurricane Katrina

  2. Does the mass of a black hole decrease due to the accretion of phantom energy?

    International Nuclear Information System (INIS)

    Gao Changjun; Chen Xuelei; Faraoni, Valerio; Shen Yougen

    2008-01-01

    According to Babichev et al., the accretion of a phantom test fluid onto a Schwarzschild black hole will induce the mass of the black hole to decrease, however the backreaction was ignored in their calculation. Using new exact solutions describing black holes in a background Friedmann-Robertson-Walker universe, we find that the physical black hole mass may instead increase due to the accretion of phantom energy. If this is the case, and the future universe is dominated by phantom dark energy, the black hole apparent horizon and the cosmic apparent horizon will eventually coincide and, after that, the black hole singularity will become naked in finite comoving time before the big rip occurs, violating the cosmic censorship conjecture.

  3. Black-hole hair loss: Learning about binary progenitors from ringdown signals

    Science.gov (United States)

    Kamaretsos, Ioannis; Hannam, Mark; Husa, Sascha; Sathyaprakash, B. S.

    2012-01-01

    Perturbed Kerr black holes emit gravitational radiation, which (for the practical purposes of gravitational-wave astronomy) consists of a superposition of damped sinusoids termed quasinormal modes. The frequencies and time constants of the modes depend only on the mass and spin of the black hole—a consequence of the no-hair theorem. It has been proposed that a measurement of two or more quasinormal modes could be used to confirm that the source is a black hole and to test if general relativity continues to hold in ultrastrong gravitational fields. In this paper, we propose a practical approach to testing general relativity with quasinormal modes. We will also argue that the relative amplitudes of the various quasinormal modes encode important information about the origin of the perturbation that caused them. This helps in inferring the nature of the perturbation from an observation of the emitted quasinormal modes. In particular, we will show that the relative amplitudes of the different quasinormal modes emitted in the process of the merger of a pair of nonspinning black holes can be used to measure the component masses of the progenitor binary.

  4. MobiQiyas: A Mobile Learning Standardized Test Preparation for Saudi Arabian Students

    Directory of Open Access Journals (Sweden)

    Mohssen Mohammed Alabbadi

    2010-10-01

    Full Text Available A mobile learning system, called MobiQiyas, for preparing Saudi Arabian students for one of the standardized tests, given by the National Center for Assessment in Higher Education (NCAHE, has been developed, using ready-made commercial products and tools. The learning material of MobiQiyas consists of practice questions with their answers, both provided by NCAHE, to be loaded by the students into their own mobile phones; after installation, the students can interact with MobiQiyas any number of times, as desired, without incurring any additional cost, other than the initial airtime cost for downloading. From total number of students taken the test, 20,000 students were randomly selected to use MobiQiyas and information was collected from them to measure their attitudes and participation of MobiQiyas. It was found that 36.1% of students had actually downloaded MobiQiyas successfully. Furthermore, a telephone survey was conducted, after the test period, on a class of 40 students in a secondary school in Riyadh, taking the same test, to measure their acceptance of MobiQiyas, using a 9-item questionnaire based on a 5-point Likert scale. The responses of the 40 students reflected high acceptance and satisfaction levels of MobiQiyas as an effective test prep tool.

  5. BlackBerry For Dummies

    CERN Document Server

    Kao, Robert

    2010-01-01

    Get the most juice out of your BlackBerry handheld!. Feature-rich and complex, the BlackBerry is the number one smartphone in the corporate world is among the most popular handhelds for business users. This new and updated edition includes all the latest and greatest information on new and current BlackBerry mobile devices. Covering a range of valuable how-to topics, this helpful guide explores the BlackBerry's most useful features, techniques for getting the most out of your BlackBerry, and practical information about power usage.: Covers all aspects of the number one smartphone in the corpor

  6. Chaos and order in models of black hole pairs

    International Nuclear Information System (INIS)

    Levin, Janna

    2006-01-01

    Chaos in the orbits of black hole pairs has by now been confirmed by several independent groups. While the chaotic behavior of binary black hole orbits is no longer argued, it remains difficult to quantify the importance of chaos to the evolutionary dynamics of a pair of comparable mass black holes. None of our existing approximations are robust enough to offer convincing quantitative conclusions in the most highly nonlinear regime. It is intriguing to note that, in three different approximations to a black hole pair built of a spinning black hole and a nonspinning companion, two approximations exhibit chaos and one approximation does not. The fully relativistic scenario of a spinning test mass around a Schwarzschild black hole shows chaos, as does the post-Newtonian Lagrangian approximation. However, the approximately equivalent post-Newtonian Hamiltonian approximation does not show chaos when only one body spins. It is well known in dynamical systems theory that one system can be regular while an approximately related system is chaotic, so there is no formal conflict. However, the physical question remains: Is there chaos for comparable mass binaries when only one object spins? We are unable to answer this question given the poor convergence of the post-Newtonian approximation to the fully relativistic system. A resolution awaits better approximations that can be trusted in the highly nonlinear regime

  7. Emission properties of Mn doped ZnO nanoparticles prepared by mechanochemical processing

    Energy Technology Data Exchange (ETDEWEB)

    Sabri, Nurul Syahidah; Yahya, Ahmad Kamal [Faculty of Applied Sciences, Universiti Teknologi MARA, Shah Alam, Selangor 40450 (Malaysia); Talari, Mahesh Kumar, E-mail: talari@gmail.com [Faculty of Applied Sciences, Universiti Teknologi MARA, Shah Alam, Selangor 40450 (Malaysia)

    2012-07-15

    Mechanochemical processing was reported to introduce lot of crystal defects which can significantly influence emission properties. Nevertheless, to the best of our knowledge, there are no reports on effect of mechanochemical processing on emission properties of transition metal ion doped ZnO. In this study, Zn{sub 1-x}Mn{sub x}O nanoparticles with different Mn content (x=0, 0.02, 0.04, 0.06, 0.08, and 0.1) were prepared by mechanochemical processing to study the effect of Mn doping and processing on emission properties. Confirmation of nanoparticles size and nanocrystalline nature of hexagonal wurtzite ZnO structure is carried out using transmission electron microscopy (TEM) and selected area electron diffraction (SAED), respectively. The samples were also characterized using Fluorescence Spectroscope before and after heat-treatment. The emission studies revealed that blue emission intensity is stronger compared to UV and green emission in contrast to the earlier reports, where other synthesis routes were employed for the ZnO nanoparticles' preparation. The blue emission originates from the zinc interstitial (Zn{sub i}) and oxygen interstitial (O{sub i}) defects, which indicate that the mechanochemical route resulted in more interstitial defects compared to oxygen substitution (O{sub Zn}) and oxygen vacancy (V{sub o}) defects which otherwise would give green emission. Mn doping resulted in shifting of near-band-edge (NBE) emission and the reduction in the intensities of NBE, blue and green emissions. The initial red shift at lower Mn content could be due to s-d and p-d exchange interactions as well as band tailing effect where as the blue shift at higher Mn content can be attributed to the Burstein-Moss shift. The reduction in emission intensity could be due to non-radiative recombination processes promoted by Mn ions with increasing Mn content. - Highlights: Black-Right-Pointing-Pointer Zn{sub 1-x}Mn{sub x}O nanoparticles were prepared by mechanochemical

  8. Sexual health among U.S. black and Hispanic men and women: a nationally representative study.

    Science.gov (United States)

    Dodge, Brian; Reece, Michael; Herbenick, Debby; Schick, Vanessa; Sanders, Stephanie A; Fortenberry, J Dennis

    2010-10-01

    Little is known about the prevalence of sexual behaviors among the black and Hispanic populations in the United States outside the context of sexual risk and disease transmission in "high-risk" samples. This study sought to establish current rates of sexual behaviors, sexual health care practices (i.e., experiences with testing and diagnosis of sexually transmitted infections [STIs]), and condom use in a probability sample of black and Hispanic adult men and women in the United States. Sexual behaviors including solo masturbation, partnered masturbation, receiving oral sex and giving oral sex, vaginal intercourse, and anal intercourse were assessed. Self-reported rates of HIV and other STI testing, and self-reported history of STI diagnosis were examined. Also assessed were rates of condom use during most recent and past 10 vaginal intercourse events. Data from a probability sample of 1246 black and Hispanic adults were analyzed to explore sexual behaviors, condom use, and STI testing and diagnosis trends. Masturbation, oral sex, and vaginal intercourse were prevalent among black and Hispanic men and women throughout the life course. Anal intercourse and same-gender sexual activities were less common. Self-reported rates of HIV testing were relatively high but varied by gender across age groups. Similarly, rates of testing for other STI were high and differed by gender across age groups. Overall rates of condom use among black and Hispanic men and women were relatively high and did not appear to be related to a variety of situational factors including location of sexual encounter, relationship status, other contraceptive use, and substance use during sexual activity. These data provide a foundation for understanding diverse sexual behaviors, sexual health-care practices, and condom use among the general population of black and Hispanic men and women in the United States. © 2010 International Society for Sexual Medicine.

  9. Electrical properties of thin epoxy-based polymer layers filled with n-carbon black particles

    Science.gov (United States)

    Klanjšek Gunde, Marta; Hauptman, Nina; Maček, Marijan

    2008-02-01

    The change of resistivity of the epoxy-based nanocomposite was studied in dependence on concentration of dispersed nanoparticles. The SU8 negative-tone photoresist was applied for the polymer matrix and the conductive carbon black powder for the fillings. The largest decrease of resistivity was obtained at 2-3 wt% of fillings whereas at loadings higher that 8 wt% it does not decreases further appreciably. The resistivity of the prepared nanocomposites becomes smaller after the UV-exposure. The applied nanofillings change the viscosity of the material but the spin-coating application still remains reliable and was approved to work well for concentrations of at least up to 3 wt%. The addition of nanofillings up to 2 wt% does not destroy the resolution of photolithography as seen on the standard test pattern with line widths from 2 to 10 μm.

  10. Black Hole Area Quantization rule from Black Hole Mass Fluctuations

    OpenAIRE

    Schiffer, Marcelo

    2016-01-01

    We calculate the black hole mass distribution function that follows from the random emission of quanta by Hawking radiation and with this function we calculate the black hole mass fluctuation. From a complete different perspective we regard the black hole as quantum mechanical system with a quantized event horizon area and transition probabilities among the various energy levels and then calculate the mass dispersion. It turns out that there is a perfect agreement between the statistical and ...

  11. Improvement of Hyperemic Myocardial Oxygen Extraction Fraction Estimation By A Diffusion Prepared Sequence

    Science.gov (United States)

    McCommis, Kyle S.; Koktzoglou, Ioannis; Zhang, Haosen; Goldstein, Thomas A.; Northrup, Benjamin E.; Li, Debiao; Gropler, Robert J.; Zheng, Jie

    2010-01-01

    Myocardial oxygen extraction fraction (OEF) during hyperemia can be estimated using a double-inversion-recovery (DIR) prepared T2-weighted black-blood sequence. Severe irregular ECG-triggering due to elevated heart rate and/or arrhythmias may render it difficult to adequately suppress the flowing left ventricle blood signal and thus potentially cause errors in the estimates of myocardial OEF. Thus, the goal of this study was to evaluate another black-blood technique, a diffusion-weighted (DW)-prepared TSE sequence for its ability to determine regional myocardial OEF during hyperemia. Control dogs and dogs with acute coronary artery stenosis were imaged with both the DIR- and DW-prepared TSE sequences at rest and during either dipyridamole or dobutamine hyperemia. Validation of MRI OEF estimates was performed using blood sampling from the artery and coronary sinus in control dogs. The two methods showed comparable correlations with blood sampling results (R2 = 0.9). Similar OEF estimations for all dogs were observed except for the group of dogs with severe coronary stenosis during dobutamine stress. In these dogs, the DW method provided more physiologically reasonable OEF (hyperemic OEF = 0.75 ± 0.08 vs resting OEF of 0.6) than the DIR method (hyperemic OEF = 0.56 ± 0.10). DW-preparation may be a valuable alternative for more accurate oxygenation measurements during irregular ECG-triggering. PMID:20512871

  12. Framing black boys: parent, teacher, and student narratives of the academic lives of black boys.

    Science.gov (United States)

    Rowley, Stephanie J; Ross, Latisha; Lozada, Fantasy T; Williams, Amber; Gale, Adrian; Kurtz-Costes, Beth

    2014-01-01

    The discourse on Black boys tends to suggest that Black boys are in complete peril. We begin with evidence that Black boys are excelling in certain contexts (i.e., in certain states, in certain schools, and in certain courses). We then discuss the ways in which the narratives used by parents, teachers, and Black boys themselves may serve to further reinforce views that Black boys are beyond hope. Research on Black parents suggests that they tend to view their sons as vulnerable and have lower expectations for sons than for daughters. Studies of teachers show that they tend to view Black boys as unteachable, as social problems, and as scary. Research on Black boys shows that they are sometimes complicit in supporting these narratives by engaging in negative or ste reotypical behavior. We also include recent research that includes counter-narratives of Black boys. We end with suggestions for future research.

  13. Preparation of nanocrystalline VN by the melamine reduction of V{sub 2}O{sub 5} xerogel and its supercapacitive behavior

    Energy Technology Data Exchange (ETDEWEB)

    Cheng Fukui [School of Chemistry and Environment, South China Normal University, Guangzhou 510006 (China); He Chun [School of Environmental Science and Engineering, Sun Yat-sen University, Guangzhou 510275 (China); Shu Dong, E-mail: dshu@scnu.edu.cn [School of Chemistry and Environment, South China Normal University, Guangzhou 510006 (China); Base of Production, Education and Research on Energy Storage and Power Battery of Guangdong Higher Education Institutes, Guangzhou 510006 (China); Key Laboratory of Electrochemical Technology on Energy Storage and Power Generation of Guangdong Higher Education Institutes, South China Normal University, Guangzhou 510006 (China); Chen Hongyu, E-mail: hychen@scnu.edu.cn [School of Chemistry and Environment, South China Normal University, Guangzhou 510006 (China); Base of Production, Education and Research on Energy Storage and Power Battery of Guangdong Higher Education Institutes, Guangzhou 510006 (China); Key Laboratory of Electrochemical Technology on Energy Storage and Power Generation of Guangdong Higher Education Institutes, South China Normal University, Guangzhou 510006 (China); Zhang Jie; Tang Shaoqing; Finlow, David E. [School of Chemistry and Environment, South China Normal University, Guangzhou 510006 (China)

    2011-12-15

    Highlights: Black-Right-Pointing-Pointer Organic nitridizing agent was employed for preparation of nanocrystalline VN. Black-Right-Pointing-Pointer The supercapacitive behavior of VN was studied by electrochemical method. Black-Right-Pointing-Pointer The supercapacitive behavior of VN was studied in three kinds of electrolyte. Black-Right-Pointing-Pointer The specific capacitance of VN was determined as 273 F g{sup -1} in 1.0 M KOH. Black-Right-Pointing-Pointer The supercapacitive mechanism and involved factor on capacitance were analyzed. - Abstract: An organic nitridizing reagent was employed in the preparation of nanocrystalline VN at 800 Degree-Sign C under a N{sub 2} atmosphere. The prepared VN was characterized by X-ray diffraction (XRD), transmission electron microscopy (TEM), Fourier transform infrared spectroscopy (FTIR) and X-ray photoelectron spectroscopy (XPS), and its supercapacitive behavior was studied by cyclic voltammetry (CV) in three different types of aqueous electrolyte, 0.5 M H{sub 2}SO{sub 4}, 2.0 M NaNO{sub 3} and 1.0 M KOH. The XRD results indicate that prepared VN has a cubic structure with space group Fm3m and a lattice parameter of 4.139 Angstrom-Sign . The nanocrystalline structure of VN with a low degree of crystallinity was confirmed by TEM imaging. The presence of oxygen on the VN surface was detected by FTIR and XPS, and its molecular composition was determined to be VN{sub 1.02}O{sub 0.1}. The specific capacitances of nanocrystalline VN were determined to be 114, 45.7 and 273 F g{sup -1} in 0.5 M H{sub 2}SO{sub 4}, 2.0 M NaNO{sub 3} and 1.0 M KOH, respectively. Thus, the KOH solution was considered the best aqueous electrolyte for the capacitive performance of VN. The supercapacitive mechanism and the factor that influenced the specific capacitance are also analyzed in this paper.

  14. The Black Family as Educator.

    Science.gov (United States)

    Wallace, Joan

    The black family is the primary socializing agent of the black child and, thus, the primary educator. The culture of blacks in America, in which the child is steeped, is unique, complex and rich-the result of a convergence and fusion of African, American, and European influences. In its education of the black child, the black family must deal,…

  15. High temperature superconductivity: Concept, preparation and testing of high Tc superconductor compounds, and applications

    International Nuclear Information System (INIS)

    Harara, Wafik

    1992-06-01

    Many studies have been carried out on high temperature superconductors with transition temperature above that of the liquid nitrogen. In this scientific study the concept and the mechanism of this phenomena are discussed, in addition the examples of preparation and testing of high temperature superconductors compounds are shown. Also the most important applications in industry are explained. (author). 15 refs., 2 tabs., 18 figs

  16. Scalar hairy black holes and scalarons in the isolated horizons formalism

    International Nuclear Information System (INIS)

    Corichi, Alejandro; Nucamendi, Ulises; Salgado, Marcelo

    2006-01-01

    The Isolated Horizons (IH) formalism, together with a simple phenomenological model for colored black holes has been used to predict nontrivial formulas that relate the ADM mass of the solitons and hairy Black Holes of Gravity-Matter system on the one hand, and several horizon properties of the black holes in the other. In this article, the IH formalism is tested numerically for spherically symmetric solutions to an Einstein-Higgs system where hairy black holes were recently found to exist. It is shown that the mass formulas still hold and that, by appropriately extending the current model, one can account for the behavior of the horizon properties of these new solutions. An empirical formula that approximates the ADM mass of hairy solutions is put forward, and some of its properties are analyzed

  17. Monopole Black Hole Skyrmions

    OpenAIRE

    Moss, Ian G; Shiiki, N; Winstanley, E

    2000-01-01

    Charged black hole solutions with pion hair are discussed. These can be\\ud used to study monopole black hole catalysis of proton decay.\\ud There also exist\\ud multi-black hole skyrmion solutions with BPS monopole behaviour.

  18. Skyrmion black hole hair: Conservation of baryon number by black holes and observable manifestations

    Energy Technology Data Exchange (ETDEWEB)

    Dvali, Gia [Arnold Sommerfeld Center, Ludwig-Maximilians-Universität, 80333 München (Germany); Max-Planck-Institut für Physik, Werner-Heisenberg-Institut, 80805 München (Germany); Center for Cosmology and Particle Physics, Department of Physics, New York University, 4 Washington Place, New York, NY 10003 (United States); Gußmann, Alexander, E-mail: alexander.gussmann@physik.uni-muenchen.de [Arnold Sommerfeld Center, Ludwig-Maximilians-Universität, 80333 München (Germany)

    2016-12-15

    We show that the existence of black holes with classical skyrmion hair invalidates standard proofs that global charges, such as the baryon number, cannot be conserved by a black hole. By carefully analyzing the standard arguments based on a Gedankenexperiment in which a black hole is seemingly-unable to return the baryon number that it swallowed, we identify inconsistencies in this reasoning, which does not take into the account neither the existence of skyrmion black holes nor the baryon/skyrmion correspondence. We then perform a refined Gedankenexperiment by incorporating the new knowledge and show that no contradiction with conservation of baryon number takes place at any stage of black hole evolution. Our analysis also indicates no conflict between semi-classical black holes and the existence of baryonic gauge interaction arbitrarily-weaker than gravity. Next, we study classical cross sections of a minimally-coupled massless probe scalar field scattered by a skyrmion black hole. We investigate how the skyrmion hair manifests itself by comparing this cross section with the analogous cross section caused by a Schwarzschild black hole which has the same ADM mass as the skyrmion black hole. Here we find an order-one difference in the positions of the characteristic peaks in the cross sections. The peaks are shifted to smaller scattering angles when the skyrmion hair is present. This comes from the fact that the skyrmion hair changes the near horizon geometry of the black hole when compared to a Schwarzschild black hole with same ADM mass. We keep the study of this second aspect general so that the qualitative results which we obtain can also be applied to black holes with classical hair of different kind.

  19. Statistical black-hole thermodynamics

    International Nuclear Information System (INIS)

    Bekenstein, J.D.

    1975-01-01

    Traditional methods from statistical thermodynamics, with appropriate modifications, are used to study several problems in black-hole thermodynamics. Jaynes's maximum-uncertainty method for computing probabilities is used to show that the earlier-formulated generalized second law is respected in statistically averaged form in the process of spontaneous radiation by a Kerr black hole discovered by Hawking, and also in the case of a Schwarzschild hole immersed in a bath of black-body radiation, however cold. The generalized second law is used to motivate a maximum-entropy principle for determining the equilibrium probability distribution for a system containing a black hole. As an application we derive the distribution for the radiation in equilibrium with a Kerr hole (it is found to agree with what would be expected from Hawking's results) and the form of the associated distribution among Kerr black-hole solution states of definite mass. The same results are shown to follow from a statistical interpretation of the concept of black-hole entropy as the natural logarithm of the number of possible interior configurations that are compatible with the given exterior black-hole state. We also formulate a Jaynes-type maximum-uncertainty principle for black holes, and apply it to obtain the probability distribution among Kerr solution states for an isolated radiating Kerr hole

  20. High-throughput preparation and testing of ion-exchanged zeolites

    International Nuclear Information System (INIS)

    Janssen, K.P.F.; Paul, J.S.; Sels, B.F.; Jacobs, P.A.

    2007-01-01

    A high-throughput research platform was developed for the preparation and subsequent catalytic liquid-phase screening of ion-exchanged zeolites, for instance with regard to their use as heterogeneous catalysts. In this system aqueous solutions and other liquid as well as solid reagents are employed as starting materials and 24 samples are prepared on a library plate with a 4 x 6 layout. Volumetric dispensing of metal precursor solutions, weighing of zeolite and subsequent mixing/washing cycles of the starting materials and distributing reaction mixtures to the library plate are automatically performed by liquid and solid handlers controlled by a single common and easy-to-use programming software interface. The thus prepared materials are automatically contacted with reagent solutions, heated, stirred and sampled continuously using a modified liquid handling. The high-throughput platform is highly promising in enhancing synthesis of catalysts and their screening. In this paper the preparation of lanthanum-exchanged NaY zeolites (LaNaY) on the platform is reported, along with their use as catalyst for the conversion of renewables